Chromane substituted benzimidazole derivatives

ABSTRACT

This invention relates to compounds of the formula (I): 
                         
or a pharmaceutically acceptable salt thereof, wherein:
 
A, B, X, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7  and R 8  are each as described herein or a pharmaceutically acceptable salt, and compositions containing such compounds and the use of such compounds in the treatment of a condition mediated by acid pump antagonistic activity such as, but not limited to, as gastrointestinal disease, gastroesophageal disease, gastroesophageal reflux disease (GERD), peptic ulcer, gastric ulcer, duodenal ulcer, NSAID-induced ulcers, gastritis, infection of  Helicobacter pylori , dyspepsia, functional dyspepsia, Zollinger-Ellison syndrome, non-erosive reflux disease (NERD), visceral pain, heartburn, nausea, esophagitis, dysphagia, hypersalivation, airway disorders or asthma.

BACKGROUND OF THE INVENTION

This invention relates to chromane substituted benzimidazole derivatives. These compounds have selective acid pump inhibitory activity. The present invention also relates to a pharmaceutical composition, method of treatment and use, comprising the above derivatives for the treatment of disease conditions mediated by acid pump modulating activity; in particular acid pump inhibitory activity.

It has been well established that proton pump inhibitors (PPIs) are prodrugs that undergo an acid-catalyzed chemical rearrangement that permits them to inhibit H⁺/K⁺-ATPase by covalently binding to its Cystein residues (Sachs, G. et. al., Digestive Diseases and Sciences, 1995, 40, 3S-23S; Sachs et. al., Annu Rev Pharmacol Toxicol, 1995, 35, 277-305.). However, unlike PPIs, acid pump antagonists inhibit acid secretion via reversible potassium-competitive inhibition of H⁺/K⁺-ATPase. SCH28080 is one of such reversible inhibitors and has been studied extensively. Other newer agents (revaprazan, soraprazan, AZD-0865 and CS-526) have entered in clinical trials confirming their efficacy in human (Pope, A.; Parsons, M., Trends in Pharmacological Sciences, 1993, 14, 323-5; Vakil, N., Alimentary Pharmacology and Therapeutics, 2004, 19, 1041-1049.). In general, acid pump antagonists are found to be useful for the treatment of a variety of diseases, including gastrointestinal disease, gastroesophageal disease, gastroesophageal reflux disease (GERD), laryngopharyngeal reflux disease, peptic ulcer, gastric ulcer, duodenal ulcer, non-steroidal anti-inflammatory drug (NSAID)-induced ulcers, gastritis, infection of Helicobacter pylori, dyspepsia, functional dyspepsia, Zollinger-Ellison syndrome, non-erosive reflux disease (NERD), visceral pain, cancer, heartburn, nausea, esophagitis, dysphagia, hypersalivation, airway disorders or asthma (hereinafter, referred as “APA Diseases”; Kiljander, Toni O, American Journal of Medicine, 2003, 115 (Suppl. 3A), 65S-71S; Ki-Baik Hahm et al., J. Clin. Biochem Nutr., 2006, 38, (1), 1-8.).

WO04/054984 refers to some compounds, such as indan-1-yl oxy benzimidazole derivatives, as acid pump antagonists.

There is a need to provide new acid pump antagonists that are good drug candidates and address unmet needs by PPIs for treating diseases. In particular, preferred compounds should bind potently to the acid pump whilst showing little affinity for other receptors and show functional activity as inhibitors of acid-secretion in stomach. They should be well absorbed from the gastrointestinal tract, be metabolically stable and possess favorable pharmacokinetic properties. They should be non-toxic. Furthermore, the ideal drug candidate will exist in a physical form that is stable, non-hygroscopic and easily formulated.

SUMMARY OF THE INVENTION

In this invention, it has now been found out that the new class of compounds having a benzimidazole structure substituted with a chromane moiety show acid pump inhibitory activity and favorable properties as drug candidates, and thus are useful for the treatment of disease conditions mediated by acid pump inhibitory activity such as APA Diseases.

The present invention provides a compound of the following formula (I):

or a pharmaceutically acceptable salt thereof, or prodrug thereof, wherein;

-   -   -A-B- represents —O—CH₂—, —S—CH₂—, —CH₂—O— or —CH₂—S—;     -   X represents an oxygen atom or NH;     -   R¹ represents a C₁-C₆ alkyl group being unsubstituted or         substituted with 1 to 2 substituents independently selected from         the group consisting of a hydroxy group and a C₁-C₆ alkoxy         group;     -   R² and R³ independently represent a hydrogen atom, a C₁-C₆ alkyl         group, a C₃-C₇ cycloalkyl group or a heteroaryl group, said         C₁-C₆ alkyl group, said C₃-C₇ cycloalkyl group and said         heteroaryl group being unsubstituted or substituted with 1 to 3         substituents independently selected from the group consisting of         a halogen atom, a hydroxy group, a C₁-C₆ alkoxy group, a C₃-C₇         cycloalkyl group, an amino group, a C₁-C₆ alkylamino group, and         a di(C₁-C₆ alkyl)amino group; or R² and R³ taken together with         the nitrogen atom to which they are attached form a 4 to 6         membered heterocyclic group being unsubstituted or substituted         with 1 to 2 substituents selected from the group consisting of a         hydroxy group, a C₁-C₆ alkyl group, a C₁-C₆ acyl group and a         hydroxy-C₁-C₆ alkyl group;     -   R⁴, R⁵, R⁶ and R⁷ independently represent a hydrogen atom, a         halogen atom, a hydroxy group, a C₁-C₆ alkyl group or a C₁-C₆         alkoxy group; and     -   R⁸ represents a hydrogen atom, a hydroxy group or a C₁-C₆ alkoxy         group.

Also, the present invention provides a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof, each as described herein, together with a pharmaceutically acceptable carrier for said compound.

Also, the present invention provides a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof, each as described herein, further comprising other pharmacologically active agent(s).

Also, the present invention provides a method of treatment of a condition mediated by acid pump inhibitory activity, in a mammalian subject, which comprises administering to a mammal in need of such treatment a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof, each as described herein.

Examples of conditions mediated by acid pump inhibitory activity include, but are not limited to, APA Diseases.

Further, the present invention provides the use of a compound of formula (I) or a pharmaceutically acceptable salt thereof, each as described herein, for the manufacture of a medicament for the treatment of a condition mediated by acid pump inhibitory activity.

Preferably, the present invention also provides the use of a compound of formula (I) or a pharmaceutically acceptable salt thereof, each as described herein, for the manufacture of a medicament for the treatment of diseases selected from APA Diseases.

The compounds of the present invention may show good bioavailability, less toxicity, good absorption, good distribution, good half life, good solubility, less protein binding affinity other than acid pump, less drug-drug interaction, and good metabolic stability.

DETAILED DESCRIPTION OF THE INVENTION

In the compounds of the present invention:

Where R¹, R², R³, R⁴, R⁵, R⁶, R⁷ or R⁸ is a C₁-C₆ alkyl group, or the substituents of the 4 to 6 membered heterocyclic group are a C₁-C₆ alkyl group, this C₁-C₆ alkyl group may be a straight or branched chain group having one to six carbon atoms, and examples include, but are not limited to, a methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, 1-ethylpropyl and hexyl. Of these, C₁-C₃ alkyl is preferred, methyl is more preferred for R¹, R⁴ R⁵, R⁶, R⁷ and R⁸ and C₁-C₃ alkyl is preferred for R²; methyl and ethyl are more preferred for R².

Where R² or R³ is a C₃-C₇ cycloalkyl group, or the substituents of R² or R³ are a C₃-C₇ cycloalkyl group, this represents a cycloalkyl group having three to seven carbon atoms, and examples include a cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl group. Of these, C₃-C₅ cycloalkyl is preferred; cyclopropyl is more preferred.

Where R² or R³ is a heteroaryl group, this represents 5 to 6-membered ring containing at least one hetero atom selected from N, O and S, and examples include, but not limited to, 2-thienyl, 2-thiazolyl, 4-thiazolyl, 2-furyl, 2-oxazolyl, 1-pyrazolyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrazinyl and 2-pyrimidinyl. Of these, heteroaryl group containing at least one nitrogen atom is preferred; 1-pyrazolyl and 2-pyridyl are more preferred.

Where R² and R³ taken together with the nitrogen atom to which they are attached form a 4 to 6 membered heterocyclic group, this 4 to 6 membered heterocyclic group represents a saturated heterocyclic group having three to five ring atoms selected from carbon atom, nitrogen atom, sulfur atom and oxygen atom other than said nitrogen atom, and examples include, but are not limited to, an azetidinyl, pyrrolidinyl, imidazolidinyl, pyrazolidinyl, piperidyl, piperazinyl, morpholino, thiomorpholino. Of these, azetidinyl, pyrrolidinyl, morpholino and piperazinyl are preferred; pyrrolidinyl is more preferred.

Where the substituent of the 4 to 6 membered heterocyclic group is a hydroxy-C₁-C₆ alkyl group, this represents said C₁-C₆ alkyl group substituted with a hydroxy group, and examples include, but are not limited to, a hydroxymethyl, 2-hydroxyethyl, 1-hydroxyethyl 3-hydroxypropyl, 2-hydroxypropyl, 2-hydroxy-1-methylethyl, 4-hydroxybutyl, 3-hydroxybutyl, 2-hydroxybutyl, 3-hydroxy-2-methtlpropyl, 3-hydroxy-1-methylpropyl, 5-hydroxypentyl and 6-hydroxyhexyl group. Of these, hydroxy-C₁-C₃ alky is preferred; hydroxymethyl is more preferred.

Where the substituents of the 4 to 6 membered heterocyclic group are a C₁-C₆ acyl group, this represents a carbonyl group substituted with said C₁-C₆ alkyl group, and examples include, but are not limited to, a formyl, acetyl, propionyl, butyryl, pentanoyl and hexanoyl group. Of these, acetyl is preferred.

Where R⁴, R⁵, R⁶, R⁷, R⁸ or the substituents of R¹, R² and R³ are a C₁-C₆ alkoxy group, this represents the oxygen atom substituted with said C₁-C₆ alkyl group, and examples include, but are not limited to, methoxy, ethoxy, propyloxy, isopropyloxy, n-butoxy, isobutoxy, sec-butoxy and tert-butoxy, pentyloxy and hexyloxy. Of these, C₁-C₃ alkoxy is preferred; methoxy is more preferred.

Where the substituents of R² or R³ are a C₁-C₆ alkylamino group, this C₁-C₆ alkylamino group represents an amino group substituted with said C₁-C₆ alkyl group. Examples include, but are not limited to, a methylamino, ethylamino, propylamino, isopropylamino, butylamino, isobutylamino, sec-butylamino, tert-butylamino, n-penthylamino, n-hexylamino. Of these, C₁-C₃ alkylamino is preferred; methylamino is more preferred.

Where the substituents of R² or R³ are a di(C₁-C₆ alkyl)amino group, this di(C₁-C₆ alkyl)amino group represents an amino group substituted with two of said C₁-C₆ alkyl groups. Examples include, but are not limited to, a dimethylamino, N-methyl-N-ethylamino, diethylamino, dipropylamino, diisopropylamino, dibutylamino, diisobutylamino, dipenthylamino, dihexylamino and N,N-di(1-methylpropyl)amino. Of these, di(C₁-C₃)alkylamino is preferred; dimethylamino and diethylamino are more preferred.

Where R⁴, R⁵, R⁶ or R⁷, or the substituents of R² or R³ are a halogen atom, this may be a fluorine, chlorine, bromine or iodine atom. Of these, fluorine is preferred.

Where -A-B— is —O—CH₂— or —S—CH₂—, -A- corresponds —O— or —S— and —B— corresponds —CH₂—.

Where -A-B— is —CH₂—O— or —CH₂—S —, -A- corresponds —CH₂— and —B— corresponds —O— or —S—.

The term “treating” and “treatment”, as used herein, refers to curative, palliative and prophylactic treatment, including reversing, alleviating, inhibiting the progress of, or preventing the disorder or condition to which such term applies, or one or more symptoms of such disorder or condition.

Preferred class of compounds of the present invention are those compounds of formula (I) or pharmaceutically acceptable salts thereof, each as described herein, in which:

-   (a) -A-B— is —O—CH₂—, —S—CH₂—, —CH₂—O— or —CH₂—S—; -   (b) -A-B— is —O—CH₂—, or —CH₂—O—; -   (c) -A-B— is —CH₂—O—; -   (d) X is an oxygen atom or NH; -   (e) X is an oxygen atom; -   (f) R¹ is a C₁-C₆ alkyl group being unsubstituted or substituted     with 1 to 2 substituents independently selected from the group     consisting of a hydroxy group and a C₁-C₆ alkoxy group; -   (g) R¹ is a C₁-C₆ alkyl group; -   (h) R¹ is a methyl group; -   (i) R² is a hydrogen atom, a C₁-C₆ alkyl group, a C₃-C₇ cycloalkyl     group or a heteroaryl group, said C₁-C₆ alkyl group, said     C₃-C₇cycloalkyl group and said heteroaryl group being unsubstituted     or substituted with 1 to 3 substituents independently selected from     the group consisting of a halogen atom, a hydroxy group, a C₁-C₆     alkoxy group, a C₃-C₇ cycloalkyl group, an amino group, a C₁-C₆     alkylamino group, and a di(C₁-C₆ alkyl)amino group; -   (j) R² is a hydrogen atom or a C₁-C₆ alkyl group being unsubstituted     or substituted with 1 to 3 substituents independently selected from     the group consisting of a hydroxy group, a C₁-C₆ alkoxy group and a     di(C₁-C₆ alkyl)amino group; -   (k) R² is a C₁-C₃ alkyl group being unsubstituted or substituted     with 1 to 3 substituents independently selected from the group     consisting of a hydroxy group and a C₁-C₃ alkoxy group; -   (l) R² is a methyl group or ethyl group, said methyl group and said     ethyl group being unsubstituted or substituted with a substituent     selected from the group consisting of a hydroxy group and a methoxy     group; -   (m) R³ is a hydrogen atom, a C₁-C₆ alkyl group, a C₃-C₇ cycloalkyl     group or a heteroaryl group, said C₁-C₆ alkyl group, said C₃-C₇     cycloalkyl group and said heteroaryl group being unsubstituted or     substituted with 1 to 3 substituents independently selected from the     group consisting of a halogen atom, a hydroxy group, a C₁-C₆ alkoxy     group, a C₃-C₇ cycloalkyl group, an amino group, a C₁-C₆ alkylamino     group, and a di(C₁-C₆ alkyl)amino group; -   (n) R³ is a hydrogen atom or a C₁-C₆ alkyl group; -   (o) R³ is a hydrogen atom or a methyl group; -   (p) R² and R³ taken together with the nitrogen atom to which they     are attached form a 4 to 6 membered heterocyclic group being     unsubstituted or substituted with 1 to 2 substituents selected from     the group consisting of a hydroxy group, a C₁-C₆ alkyl group, a     C₁-C₆ acyl group and a hydroxy-C₁-C₆ alkyl group; -   (q) R² and R³ taken together with the nitrogen atom to which they     are attached form an azetidinyl group, a pyrrolidinyl group, a     piperazinyl group or a morpholino group, said azetidinyl group, said     pyrrolidinyl group, said piperazinyl group and said morpholino group     being unsubstituted or substituted with 1 to 2 substituents selected     from the group consisting of a hydroxy group, a C₁-C₆ alkyl group, a     C₁-C₆ acyl group and a hydroxy-C₁-C₆ alkyl group; -   (r) R² and R³ taken together with the nitrogen atom to which they     are attached form a pyrrolidinyl group being unsubstituted or     substituted with a substituent selected from the group consisting of     a hydroxy group and a hydroxy-C₁-C₃ alkyl group; -   (s) R⁴ is a hydrogen atom, a halogen atom, a hydroxy group, a CHECK     alkyl group or a C₁-C₆ alkoxy group; -   (t) R⁴ is a hydrogen atom, a halogen atom or a C₁-C₆ alkyl group; -   (u) R⁴ is a hydrogen atom, a halogen atom or a C₁-C₃ alkyl group; -   (v) R⁴ is a hydrogen atom, a fluorine atom, a chlorine atom or a     methyl group; -   (w) R⁵ is a hydrogen atom, a halogen atom, a hydroxy group, a C₁-C₆     alkyl group or a C₁-C₆ alkoxy group; -   (x) R⁵ is a hydrogen atom; -   (y) R⁶ is a hydrogen atom, a halogen atom, a hydroxy group, a C₁-C₆     alkyl group or a C₁-C₆ alkoxy group; -   (z) R⁶ is a hydrogen atom or a halogen atom; -   (aa) R⁶ is a hydrogen atom or a fluorine atom or a chlorine atom; -   (bb) R⁷ is a hydrogen atom, a halogen atom, a hydroxy group, a C₁-C₆     alkyl group or a C₁-C₆ alkoxy group; -   (cc) R⁷ is a hydrogen atom or a halogen atom; -   (dd) R⁷ is a hydrogen atom or a fluorine atom or a chlorine atom; -   (ee) R⁸ is a hydrogen atom, a hydroxy group or a C₁-C₆ alkoxy group; -   (ff) R⁸ is a hydrogen atom or a hydroxy group; and -   (gg) R⁸ is a hydrogen atom.

Of these classes of compounds, any combination among (a) to (gg) is also preferred.

Preferred compound of the present invention are those compounds of formula (I) or a pharmaceutically acceptable salt thereof, each as described herein, in which:

-   (A) -A-B— is —O—CH₂—, —S—CH₂—, —CH₂—O— or —CH₂—S—; X is an oxygen     atom; R¹ is a C₁-C₆ alkyl group being unsubstituted or substituted     with 1 to 2 substituents independently selected from the group     consisting of a hydroxy group and a C₁-C₆ alkoxy group; R² and R³     are independently a C₁-C₆ alkyl group or a C₃-C₇ cycloalkyl group,     said C₁-C₆ alkyl group and said C₃-C₇ cycloalkyl group being     unsubstituted or substituted with 1 to 3 substituents independently     selected from the group consisting of a halogen atom, a hydroxy     group, a C₁-C₆ alkoxy group, a C₃-C₇ cycloalkyl group and a di(C₁-C₆     alkyl)amino group; or R² and R³ taken together with the nitrogen     atom to which they are attached form an azetidinyl group, a     pyrrolidinyl group, a piperazinyl group or a morpholino group, said     azetidinyl group, said pyrrolidinyl group, said piperazinyl group     and said morpholino group being unsubstituted or substituted with a     substituent selected from the group consisting of a hydroxy group, a     C₁-C₆ alkyl group, a C₁-C₆ acyl group and a hydroxy-C₁-C₆ alkyl     group; R⁴, R⁵, R⁶ and R⁷ are independently a hydrogen atom, a     halogen atom or a C₁-C₆ alkyl group; and R⁸ is a hydrogen atom; -   (B) -A-B— is —O—CH₂— or —CH₂—O—; X is an oxygen atom; R¹ is a C₁-C₆     alkyl group; R² and R³ are independently a C₁-C₆ alkyl group being     unsubstituted or substituted with 1 to 3 substituents independently     selected from the group consisting of a hydroxy group and a C₁-C₆     alkoxy group and; or R² and R³ taken together with the nitrogen atom     to which they are attached form a pyrrolidinyl group being     unsubstituted or substituted with a substituent selected from the     group consisting of a hydroxy group, a C₁-C₆ alkyl group and a     hydroxy-C₁-C₆ alkyl group; R⁴, R⁵, R⁶ and R⁷ are independently a     hydrogen atom, a halogen atom or a C₁-C₆ alkyl group; and R⁸ is a     hydrogen atom; -   (C) -A-B— is —CH₂—O—; X is an oxygen atom; R¹ is a C₁-C₆ alkyl     group; R² and R³ are independently a C₁-C₆ alkyl group; or R² and R³     taken together with the nitrogen atom to which they are attached     form a pyrrolidinyl group; R⁴, R⁵, R⁶ and R⁷ are independently a     hydrogen atom, a halogen atom or a C₁-C₆ alkyl group; and R⁸ is a     hydrogen atom; -   (D) -A-B— is —CH₂—O—; X is an oxygen atom: R¹ is a C₁-C₆ alkyl     group; R² and R³ are independently a C₁-C₆ alkyl group; or R² and R³     taken together with the nitrogen atom to which they are attached     form a pyrrolidinyl group; R⁴, R⁶ and R⁷ are independently a     hydrogen atom, a halogen atom or a C₁-C₆ alkyl group; and R⁵ and R⁸     are a hydrogen atom; -   (E) -A-B— is —CH₂—O—; X is an oxygen atom; R¹ is a C₁-C₆ alkyl     group; R² and R³ are independently a C₁-C₆ alkyl group; R⁴, R⁶ and     R⁷ are independently a hydrogen atom, a halogen atom or a C₁-C₆     alkyl group; and R⁵ and R⁸ are a hydrogen atom.

One embodiment of the invention provides a compound selected from the group consisting of:

-   4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide; -   4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-6-(pyrrolidin-1-ylcarbonyl)-1H-benzimidazole; -   4-[(5-fluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide;     or a pharmaceutical acceptable salt thereof.

Another embodiment of the invention provides a compound selected from the group consisting of:

-   (−)-4-[((4S)-5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxami     de; -   (−)-4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-6-(pyrrolidin-1-ylcarbonyl)-1H-benzimidazol     e; -   (−)-4-[(5-fluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide;     or a pharmaceutical acceptable salt thereof.

Pharmaceutically acceptable salts of a compound of formula (I) include the acid addition salts and base salts (including disalts) thereof.

Suitable acid addition salts are formed from acids which form non-toxic salts. Examples include the acetate, adipate, aspartate, benzoate, besylate, bicarbonate/carbonate, bisulphate/sulphate, borate, camsylate, citrate, cyclamate, edisylate, esylate, formate, fumarate, gluceptate, gluconate, glucuronate, hexafluorophosphate, hibenzate, hydrochloride/chloride, hydrobromide/bromide, hydroiodide/iodide, isethionate, lactate, malate, maleate, malonate, mesylate, methylsulphate, naphthylate, 2-napsylate, nicotinate, nitrate, orotate, oxalate, palmitate, pamoate, phosphate/hydrogen phosphate/dihydrogen phosphate, pyroglutamate, saccharate, stearate, succinate, tannate, tartrate, tosylate, trifluoroacetate and xinofoate salts.

The base addition salts include alkali metal salts, for example lithium salts, sodium salts and potassium salts; alkaline earth metal salts, for example calcium salts and magnesium salts; ammonium salts; organic base salts, for example triethylamine salts, diisopropylamine salts and cyclohexylamine salts; and the like. Preferred salts are alkali metal salts and more preferred salts are sodium salts.

For a review on suitable salts, see “Handbook of Pharmaceutical Salts: Properties, Selection, and Use” by Stahl and Wermuth (Wiley-VCH, Weinheim, Germany, 2002). A pharmaceutically acceptable salt of a compound of formula (I) may be readily prepared by mixing together solutions of the compound of formula (I) and the desired acid or base, as appropriate. The salt may precipitate from solution and be collected by filtration or may be recovered by evaporation of the solvent. The degree of ionization in the salt may vary from completely ionized to almost non-ionized.

Pharmaceutically acceptable salts of the compounds of formula (I) thereof include both unsolvated and solvated forms. The term “solvate” is used herein to describe a molecular complex comprising a compound of the invention and one or more pharmaceutically acceptable solvent molecules, for example, ethanol. The term ‘hydrate’ is employed when said solvent is water.

Pharmaceutically acceptable solvates in accordance with the invention include hydrates and solvates wherein the solvent of crystallization may be isotopically substituted, e.g. D₂O, d₆-acetone, d₆-DMSO.

Included within the scope of the invention are complexes such as clathrates, drug-host inclusion complexes wherein, in contrast to the aforementioned solvates, the drug and host are present in stoichiometric or non-stoichiometric amounts. Also included are complexes of the drug containing two or more organic and/or inorganic components which may be in stoichiometric or non-stoichiometric amounts. The resulting complexes may be ionized, partially ionized, or non-ionized. For a review of such complexes, see J Pharm Sci, 64 (8), 1269-1288 by Haleblian (August 1975).

The compounds of formula (I) may exist in one or more crystalline forms. These polymorphs, including mixtures thereof are also included within the scope of the present invention.

The compounds of formula (I) containing one or more asymmetric carbon atoms can exist as two or more stereoisomers.

Included within the scope of the present invention are all stereoisomers of the compounds of formula (I), including compounds exhibiting more than one type of isomerism, and mixtures of one or more thereof.

The present invention includes all pharmaceutically acceptable isotopically-labeled compounds of formula (I) wherein one or more atoms are replaced by atoms having the same atomic number, but an atomic mass or mass number different from the atomic mass or mass number usually found in nature.

Examples of isotopes suitable for inclusion in the compounds of the invention include isotopes of hydrogen, such as ²H and ³H, carbon, such as ¹¹C, ¹³C and ¹⁴C, chlorine, such as ³⁶Cl, fluorine, such as ¹⁸F, iodine, such as ¹²³I and ²⁵¹I, nitrogen, such as ¹³N and ¹⁵N, oxygen, such as ¹⁵O, ¹⁷O and ¹⁸O, phosphorus, such as ³²P, and sulphur, such as ³⁵S.

Certain isotopically-labeled compounds of formula (I), for example, those incorporating a radioactive isotope, are useful in drug and/or substrate tissue distribution studies. The radioactive isotopes tritium, i.e. ³H, and carbon-14, i.e. ¹⁴C, are particularly useful for this purpose in view of their ease of incorporation and ready means of detection.

Substitution with heavier isotopes such as deuterium, i.e. ²H, may afford certain therapeutic advantages resulting from greater metabolic stability, for example, increased in vivo half-life or reduced dosage requirements, and hence may be preferred in some circumstances.

Substitution with positron emitting isotopes, such as ¹¹C, ¹⁸F, ¹⁵O and ¹³N, can be useful in Positron Emission Topography (PET) studies for examining substrate receptor occupancy.

Isotopically-labeled compounds of formula (I) can generally be prepared by conventional techniques known to those skilled in the art or by processes analogous to those described in the accompanying examples and preparations using an appropriate isotopically-labeled reagents in place of the non-labeled reagent previously employed.

Also within the scope of the invention are so-called “prodrugs” of the compounds of formula (I). Thus certain derivatives of compounds of formula (I) which may have little or no pharmacological activity themselves can, when administered into or onto the body, be converted into compounds of formula (I) having the desired activity, for example, by hydrolytic cleavage. Such derivatives are referred to as “prodrugs”. Further information on the use of prodrugs may be found in Pro-drugs as Novel Delivery Systems, Vol. 14, ACS Symposium Series (T Higuchi and W Stella) and Bioreversible Carriers in Drug Design, Pergamon Press, 1987 (ed. E B Roche, American Pharmaceutical Association).

Prodrugs in accordance with the invention can, for example, be produced by replacing appropriate functionalities present in the compounds of formula (I) with certain moieties known to those skilled in the art as ‘pro-moieties’ as described, for example, in Design of Prodrugs by H Bundgaard (Elsevier, 1985). Some examples of prodrugs in accordance with the invention include:

-   (i) where the compound of formula (I) contains an alcohol     functionality (—OH), compounds wherein the hydroxy group is replaced     with a moiety convertible in vivo into the hydroxy group. Said     moiety convertible in vivo into the hydroxy group means a moiety     transformable in vivo into a hydroxyl group by e.g. hydrolysis     and/or by an enzyme, e.g. an esterase. Examples of said moiety     include, but are not limited to, ester and ether groups which may be     hydrolyzed easily in vivo. Preferred are the moieties replaced the     hydrogen of hydroxy group with acyloxyalkyl,     1-(alkoxycarbonyloxy)alkyl, phthalidyl and acyloxyalkyloxycarbonyl     such as pivaloyloxymethyloxycarbonyl. -   (ii) where the compound of the formula (I) contains an amino group,     an amide derivative prepared by reacting with a suitable acid halide     or a suitable acid anhydride is exemplified as a prodrug. A     particularly preferred amide derivative as a prodrug is     —NHCO(CH₂)₂OCH₃, —NHCOCH(NH₂)CH₃ or the like.

Further examples of replacement groups in accordance with the foregoing examples and examples of other prodrug types may be found in the aforementioned references.

All of the compounds of the formula (I) can be prepared by the procedures described in the general methods presented below or by the specific methods described in the examples section and the preparations section, or by routine modifications thereof. The present invention also encompasses any one or more of these processes for preparing the compounds of formula (I), in addition to any novel intermediates used therein.

General Synthesis

The compounds of the present invention may be prepared by a variety of processes well known for the preparation of compounds of this type, for example as shown in the following Method A to B.

All starting materials in the following general syntheses may be commercially available or obtained by the following Method C to D or conventional methods known to those skilled in the art, such as WO 2000078751 and WO 2004054984 and the disclosures of which are incorporated herein by references.

Method A

This illustrates the preparation of compounds of formula (I).

In Reaction Scheme A, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, A and B are each as defined above; Hal is a halogen atom, preferably a bromine atom; Prot¹ is a hydroxy-protecting group or an amino-protecting group; Prot² is a nitrogen-protecting group; Lv is a leaving group; R^(1a) is R¹ as defined above or R¹ wherein hydroxy group is protected by a hydroxy-protecting group; R^(2a) is R² as defined above, R² wherein hydroxy group is protected by a hydroxy-protecting group, or R² wherein amino group or C₁-C₆ alkylamino group is protected by an amino-protecting group; R^(3d) is R³ as defined above, R³ wherein hydroxy group is protected by a hydroxy-protecting group, or R³ wherein amino group or C₁-C₆ alkylamino group is protected by an amino-protecting group; R^(4a) is R⁴ as defined above or R⁴ wherein hydroxy group is protected by a hydroxy-protecting group; R^(5a) is R⁵ as defined above or R⁵ wherein hydroxy group is protected by a hydroxy-protecting group; R^(6a) is R⁶ as defined above or R⁶ wherein hydroxy group is protected by a hydroxy-protecting group; R^(7a) is R⁷ as defined above or R⁷ wherein hydroxy group is protected by a hydroxy-protecting group; R^(8a) is R⁸ as defined above or R⁸ wherein hydroxy group is protected by a hydroxy-protecting group; and the same shall apply hereinafter.

The term “leaving group”, as used herein, signifies a group capable of being substituted by nucleophilic groups, such as a hydroxy group or amines and examples of such leaving groups include a halogen atom, a alkylsulfonyloxy group, a halogenoalkylsulfonyloxy group and a phenylsulfonyloxy group. Of these, a bromine atom, a chlorine atom, a methylsulfonyloxy group, a trifluoromethylsulfonyloxy group and a 4-methylphenylsulfonyloxy group are preferred.

The term “hydroxy-protecting groups”, as used herein, signifies a protecting group capable of being cleaved by various means to yield a hydroxy group, such as hydrogenolysis, hydrolysis, electrolysis or photolysis, and such hydroxy-protecting groups are described in Protective Groups in Organic Synthesis edited by T. W. Greene et al. (John Wiley & Sons, 1999). Such as for example, C₁-C₄ alkoxycarbonyl, C₁-C₄ alkylcarbonyl, tri-C₁-C₄ alkylsilyl or tri-C₁-C₄ alkylarylsilyl groups, and C₁-C₄ alkoxy-C₁-C₄ alkyl groups. Suitable hydroxy-protecting groups include acetyl and tert-butyidimethylsilyl.

The term “amino or nitrogen protecting groups”, as used herein, signifies a protecting group capable of being cleaved by various means to yield a hydroxy group, such as hydrogenolysis, hydrolysis, electrolysis or photolysis, and such amino or nitrogen protecting groups are described in Protective Groups in Organic Synthesis edited by T. W. Greene et al. (John Wiley & Sons, 1999). Such as for example, C₁-C₄ alkoxycarbonyl, C₁-C₄ alkylcarbonyl, tri-C₁-C₄ alkylsilyl, phenylsulfonyloxy group or aralkyl groups. Suitable amino or nitrogen protecting groups include benzyl, tert-butoxycarbonyl and toluensulfonyl.

(Step A1)

In this step, the compound (IV) is prepared by amide formation of the amino group of the compound of formula (II), which is commercially available or may be prepared by the methods described in WO 2004054984, with acid anhydride (III).

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; carboxylic acids, such as acetic acid, formic acid, propanoic acid; Of these solvents, acetic acid or the reaction in the absence of solvents is preferred.

The reaction may be carried out in the presence or absence of a base. There is likewise no particular restriction on the nature of the bases used, and any base commonly used in reactions of this type may equally be used here. Examples of such bases include: amines, such as N-methylmorpholine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine, dicyclohexylamine, N-methylpiperidine, pyridine, 4-pyrrolidinopyridine, picoline, 4-(N,N-dimethylamino)pyridine, 2,6-di(tert-butyl)-4-methylpyridine, quinoline, N,N-dimethylaniline, N,N-diethylaniline, 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). Of these, the reaction in the absence of base is preferred.

The reaction may be carried out in the presence of an acid. There is likewise no particular restriction on the nature of the acids used, and any acid commonly used in reactions of this type may equally be used here. Examples of such acids include: acids, such as hydrochloric acid, sulfuric acid or hydrobromic acid; sulfonic acids, such as methanesulfonic acid or toluenesulfonic acid. Of these, sulfuric acid is preferred.

The reaction can take place over a wide range of temperatures and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 10 minutes to about 24 hours will usually suffice.

(Step A2)

In this step, the compound of formula (V) is prepared by substitution of the halogen atom of the compound of formula (IV) with metal cyanide.

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide, 1-methylpyrrolidin-2-one and hexamethylphosphoric triamide; Of these solvents, N,N-dimethylformamide is preferred.

The reaction is carried out in the presence of a metal cyanide reagent. There is no particular restriction on the nature of the metal cyanide reagent to be employed, and any metal cyanide reagent commonly used in reactions of this type may equally be used here. Examples of such metal cyanide reagents include: zinc(II) cyanide, copper(I) cyanide, potassium cyanide and sodium cyanide; Of these, zinc(II) cyanide is preferred.

The reaction is carried out in the presence or absence of a palladium catalyst. There is no particular restriction on the nature of the palladium catalyst to be employed, and any palladium catalyst commonly used in reactions of this type may equally be used here. Examples of such palladium catalysts include: a palladium metal, palladium chloride, palladium(II) acetate, tris(dibenzylideneacetone)dipalladiumchloroform, allyl palladium chloride, [1,2-bis(diphenylphosphino)ethane]palladium dichloride, bis(tri-o-tolylphosphine)palladium dichloride, bis(triphenylphosphine)palladium dichloride, tetrakis(triphenylphosphine)palladium, dichloro[1,1′-bis(diphenylphosphino)ferrocene]palladium, or a catalyst produced in solution by adding a ligand into the reaction solution of these. The ligand added into the reaction solution may be a phosphoric ligand such as triphenylphosphine, 1,1′-bis(diphenylphosphino)ferrocene, bis(2-diphenylphosphinophenyl) ether 2,2′-bis(diphenylphosphino)-1,1′-binaphthol, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, tri-o-tolylphosphine, 2-diphenylphosphino-2′-methoxy-1,1′-binaphthyl or 2,2-bis(diphenylphosphino)-1,1′-binaphthyl. Of these, tetrakis(triphenylphosphine)palladium is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 50° C. to about 150° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 30 minutes to about 24 hours will usually suffice.

In this reaction, microwave can be employed to accelerate the reaction. In the case of employing microwave in sealed tube, the reaction at a temperature may be from about 50° C. to about 180° C. and the reaction time from about 5 minutes to about 12 hours will usually suffice.

(Step A3)

In this step, the compound of formula (VI) is prepared by reduction and cyclization of the compound of formula (V).

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; alcohols, such as methanol, ethanol, propanol, 2-propanol and butanol; nitrites, such as acetonitrile and benzonitrile; Of these solvents, the reaction in the absence of solvent or ethanol is preferred.

The reaction is carried out in the presence of a reducing agent. There is likewise no particular restriction on the nature of the reducing agents used, and any reducing agent commonly used in reactions of this type may equally be used here. Examples of such reducing agents include: a combination of metals, such as zinc or iron, and acids, such as hydrochloric acid, acetic acid and acetic acid-ammonium chloride complex. Of these, the combination of iron and acetic acid is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 150° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 30 minutes to about 24 hours will usually suffice.

(Step A4)

In this step, the compound (VII) is prepared by hydrolysis of the cyanide group of the compound of formula (VI) with a base or an acid.

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; alcohols, such as methanol, ethanol, propanol, 2-propanol, ethylene glycol and butanol; nitrites, such as acetonitrile and benzonitrile; sulfoxides, such as dimethyl sulfoxide and sulfolane; water; or mixed solvents thereof. Of these solvents, ethylene glycol is preferred.

The reaction may be carried out in the presence of a base. There is likewise no particular restriction on the nature of the bases used, and any base commonly used in reactions of this type may equally be used here. Examples of such bases include: alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal carbonates, such as lithium carbonate, sodium carbonate and potassium carbonate. Of these, potassium hydroxide is preferred.

The reaction may be carried out in the presence of an acid. There is likewise no particular restriction on the nature of the acids used, and any acid commonly used in reactions of this type may equally be used here. Examples of such acids include: carboxylic acids, such as acetic acid or propionic acid; acids, such as hydrochloric acid, sulfuric acid or hydrobromic acid. Of these, hydrochloric acid is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 150° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 60 minutes to about 24 hours, will usually suffice.

In this reaction, microwave can be employed to accelerate the reaction. In the case of employing microwave in sealed tube, the reaction at a temperature may be from about 50° C. to about 180° C. and the reaction time from about 5 minutes to about 12 hours will usually suffice.

(Step A5)

In this step, the compound (IX) is prepared by amidation of the compound of formula (VII) with the compound of formula (VIII), which is commercially available or described in J. Org. Chem., 5935 (1990) and Canadian Journal of Chemistry, 2028 (1993) followed by the introduction of the protecting group 2 (Prot²) and deprotection of the protecting group 1 (Prot¹). The compound of formula (IX) may be prepared alternatively by the following Method E.

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; nitriles, such as acetonitrile and benzonitrile; sulfoxides, such as dimethyl sulfoxide and sulfolane; or mixed solvents thereof. Of these, N,N-dimethylformamide is preferred.

The reaction is carried out in the presence of a base. There is likewise no particular restriction on the nature of the bases used, and any base commonly used in reactions of this type may equally be used here. Examples of such bases include: amines, such as N-methylmorpholine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine, dicyclohexylamine, N-methylpiperidine, pyridine, 4-pyrrolidinopyridine, picoline, 4-(N,N-dimethylamino)pyridine, 2,6-di(tert-butyl)-4-methylpyridine, quinoline, N,N-dimethylaniline, N,N-diethylaniline, DBN, DABCO and DBU. Of these, triethylamine or diisopropylethylamine is preferred.

The reaction is carried out in the presence of a condensing agent. There is likewise no particular restriction on the nature of the condensing agents used, and any condensing agent commonly used in reactions of this type may equally be used here. Examples of such condensing agents include: 2-halo-1-lower alkyl pyridinium halides, such as 2-chloro-1-methylpyridinium iodide and 2-bromo-1-ethylpyridinium tetrafluoroborate (BEP); diarylphosphorylazides, such as diphenylphosphorylazide (DPPA); chloroformates, such as ethyl chloroformate and isobutyl chloroformate; phosphorocyanidates, such as diethyl phosphorocyanidate (DEPC); imidazole derivatives, such as N,N′-carbonyldiimidazole (CDI); carbodiimide derivatives, such as N,N′-dicyclohexylcarbodiimide (DCC) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI); iminium salts, such as 2-(1H-benzotriazol-1-yl) 1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU) and tetramethyl fluoroformamidinium hexafluoro phosphate (TFFH); and phosphonium salts, such as benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate (BOP) and bromo-tris-pyrrolidino-phosphonium hexafluorophosphate (PyBrop). Of these, EDCI or HBTU is preferred.

Reagents, such as 4-(N,N-dimethylamino)pyridine (DMAP), and 1-hydroxybenztriazole (HOBt), may be employed for this step. Of these, HOBt is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 80° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 30 minutes to about 48 hours, will usually suffice.

(Introduction of the Nitrogen-Protecting Group Prot²)

This reaction is described in detail by T. W. Greene et al., Protective Groups in Organic Synthesis, 369-453, (1999), the disclosures of which are incorporated herein by reference. The following exemplifies a typical reaction involving the protecting group of alkoxycarbonyl or arylsulfonyl.

Examples of the nitrogen-protecting group halide or anhydride usable in the above reaction include 4-methylphenylsulfonyl chloride, phenylsulfonyl chloride or di-tert-butyl-dicarbonate; of these 4-methylsulfonyl chloride or di-tert-butyl-dicarbonate is preferred.

Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; 6 amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; nitriles, such as acetonitrile and benzonitrile; sulfoxides, such as dimethyl sulfoxide and sulfolane; alcohols, such as methanol, ethanol, propanol, 2-propanol, ethylene glycol and butanol; or mixed solvents thereof. Of these, N,N-dimethylformamide is preferred.

Examples of such bases include: alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal hydrides, such as lithium hydride, sodium hydride and potassium hydride; alkali metal alkoxides, such as sodium methoxide, sodium ethoxide and potassium tert-butoxide; alkali metal carbonates, such as lithium carbonate, sodium carbonate and potassium carbonate; alkali metal hydrogencarbonates, such as lithium hydrogencarbonate, sodium hydrogencarbonate and potassium hydrogencarbonate; amines, such as N-methylmorpholine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine, dicyclohexylamine, N-methylpiperidine, pyridine, 4-pyrrolidinopyridine, picoline, 4-(N,N-dimethylamino)pyridine, 2,6-di(tert-butyl)-4-methylpyridine, quinoline, N,N-dimethylaniline, N,N-diethylaniline, DBN, DABCO and DBU; alkali metal amides, such as lithium amide, sodium amide, potassium amide, lithium diisopropyl amide, potassium diisopropyl amide, sodium diisopropyl amide, lithium bis(trimethylsilyl)amide and potassium bis(trimethylsilyl)amide; or mixed bases thereof. Of these, sodium hydride or triethylamine is preferred.

(Deprotection of Prot¹)

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; alcohols, such as methanol, ethanol, propanol, 2-propanol and butanol; carboxylic acid, such as acetic acid or formic acid; Of these solvents, acetic acid or tetrahydrofuran is preferred.

The reaction is carried out in the presence of a palladium catalyst under the hydrogen gas. There is no particular restriction on the nature of the palladium catalyst to be employed, and any palladium catalyst commonly used in reactions of this type may equally be used here. Examples of such palladium catalysts include: palladium metal, palladium-carbon, palladium hydroxide, Of these, palladium-carbon or palladium hydroxide is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 10 minutes to about 24 hours, will usually suffice.

(Step A6)

In this step, the compound (I) is prepared by coupling reaction of the compound of formula (IX) and the compound of formula (Xa) (A6-a) or the substitution reaction using the same starting material and the compound of formula (Xb) (A6-b), provided when X is NH, only Method A6-b is available. The compounds of formula (Xa) and (Xb) are commercially available or may be prepared by the methods described in the following Method C, D or Synthesis 595 (1933)

(A6-a) Coupling Reaction

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; nitriles, such as acetonitrile and benzonitrile; or mixed solvents thereof. Of these, tetrahydrofuran or toluene is preferred.

The reaction is carried out in the presence of a condensing agent. There is likewise no particular restriction on the nature of the condensing agents used, and any condensing agent commonly used in reactions of this type may equally be used here. Examples of such condensing agents include: azodicarboxylic acid di-lower alkyl esters, such as diethyl azodicarboxylate (DEAD), diisopropyl azodicarboxylate (DIAD) and di-tertbutyl azodicarboxylate (DTAD); azodicarboxamides, such as N,N,N′,N′-tetraisopropylazodicarboxamide (TIPA), 1,1′-(azodicarbonyl)dipiperidine (ADDP) and N,N,N′,N′-tetramethylazodicarboxamide (TMAD); phosphoranes, such as (cyanomethylene)tributylphosphorane (CMBP) and (cyanomethylene)trimethylphosphorane (CMMP). Of these, DIAD or ADDP is preferred.

Phosphine reagents, such as triphenylphosphine, trimethylphosphine and tributylphosphine, may be employed for this step. Of these, triphenylphosphine or tributylphosphine is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 120° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 60 minutes to about 48 hours, will usually suffice.

(A6-b) Substitution Reaction

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; alcohols, such as methanol, ethanol, propanol, 2-propanol and butanol; nitrites, such as acetonitrile and benzonitrile; sulfoxides, such as dimethyl sulfoxide and sulfolane; ketones, such as acetone and diethylketone; or mixed solvents thereof. Of these solvents, N,N-dimethylacetamide or acetone is preferred.

The reaction is carried out in the presence or absence of a base. There is likewise no particular restriction on the nature of the bases used, and any base commonly used in reactions of this type may equally be used here. Examples of such bases include: alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal hydrides, such as lithium hydride, sodium hydride and potassium hydride; alkali metal alkoxides, such as sodium methoxide, sodium ethoxide and potassium tert-butoxide; alkali metal carbonates, such as lithium carbonate, sodium carbonate and potassium carbonate; alkali metal hydrogencarbonates, such as lithium hydrogencarbonate, sodium hydrogencarbonate and potassium hydrogencarbonate; amines, such as N-methylmorpholine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine, dicyclohexylamine, N-methylpiperidine, pyridine, 4-pyrrolidinopyridine, picoline, 4-(N,N-dimethylamino pyridine, 2,6-di(tert-butyl)-4-methylpyridine, quinoline, N,N-dimethylaniline, N,N-diethylaniline, DBN, DABCO and DBU; alkali metal amides, such as lithium amide, sodium amide, potassium amide, lithium diisopropyl amide, potassium diisopropyl amide, sodium diisopropyl amide, lithium bis(trimethylsilyl)amide and potassium bis(trimethylsilyl)amide. Of these, sodium hydride or potassium carbonate is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 30 minutes to about 24 hours will usually suffice.

(Deprotection of Prot²)

The deprotection reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; alcohols, such as methanol, ethanol, propanol, 2-propanol, ethylene glycol and butanol; nitrites, such as acetonitrile and benzonitrile; sulfoxides, such as dimethyl sulfoxide and sulfolane; water; or mixed solvents thereof. Of these solvents, methanol, tetrahydrofuran, water, or mixed solvents thereof is preferred.

The reaction may be carried out in the presence of a base. There is likewise no particular restriction on the nature of the bases used, and any base commonly used in reactions of this type may equally be used here. Examples of such bases include; alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal carbonates, such as lithium carbonate, sodium carbonate and potassium carbonate. Of these, lithium hydroxide or sodium hydroxide is preferred.

The deprotection reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 130° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 10 minutes to about 24 hours, will usually suffice.

(Deprotection of Hydroxy-Protecting Group)

In the case where R^(1a), R^(2a), R^(3a), R^(4a), R^(5a), R^(6a), R^(7a), R^(8a) has a protected hydroxy group, the deprotection reaction will follow to yield a hydroxy group. This reaction is described in detail by T. W. Greene et al., Protective Groups in Organic Synthesis, 369-453, (1999), the disclosures of which are incorporated herein by reference. The following exemplifies a typical reaction involving the protecting group tert-butyldimethylsilyl.

The deprotection of the hydroxyl groups is carried out with an acid, such as acetic acid, hydrogen fluoride, hydrogen fluoride-pyridine complex, or fluoride ion, such as tetrabutylammonium fluoride (TBAF).

The deprotection reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include, but are not limited to: alcohol, such as methanol, ethanol or mixed solvents thereof.

The deprotection reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 10 minutes to about 24 hours, will usually suffice.

Method B

This illustrates the preparation of compounds of formula (I).

In Reaction Scheme B, Alk is a C₁-C₆ alkyl group, preferably a methyl group and the same shall apply hereinafter. (Step B1)

In this step, the compound of formula (XI) is prepared by esterification of the compound of formula (VII), which may be prepared by the Step A4 of the Method A, with the corresponding alcohol followed by the introduction of Prot² and the deprotection of the Prot¹. The introduction and deprotection of the protecting groups may be carried out under the same condition as described in Step A5 of Method A.

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; nitriles, such as acetonitrile and benzonitrile; sulfoxides, such as dimethyl sulfoxide and sulfolane; ketones, such as acetone and diethylketone; Of these solvents, the reaction in the absence of solvents preferred.

The reaction may be carried out in the presence of an acid. There is likewise no particular restriction on the nature of the acids used, and any acid commonly used in reactions of this type may equally be used here. Examples of such acids include: acids, such as hydrochloric acid, sulfuric acid or hydrobromic acid; sulfonic acids, such as methanesulfonic acid or toluenesulfonic acid; acid chloride, such as oxalyl chloride or thionyl chloride. Of these, hydrochloric acid or thionyl chloride is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, we find it convenient to carry out the reaction at a temperature of from 0° C. to 120° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 5 minutes to 24 hours, will usually suffice.

(Step B2)

In this step, the compound (XII) is prepared by reaction of the compound of formula (XI) with the compound of the formula (Xa) or (Xb), which is commercially available or may be prepared by the methods described in the following Method C, D or Synthesis 595 (1983). The reaction may be carried out under the same condition as described in Step A6 of Method A.

(Step B3)

In this step, the compound (XIII) is prepared by hydrolysis of the compound of formula (XII). The reaction may be carried out under the same condition as described in Step A4 of Method A.

(Step B4)

In this step, the compound (I) is prepared by amidation of the compound of formula (XIII) with the compound of formula (VIII). The reaction may be carried out under the same condition as described in Step A5 of Method A.

Method C

This illustrates the preparation of compounds of formula (Xa-1) and (Xb-1) wherein A is CH₂.

In Reaction Scheme C, Hal is a halogen atom, R^(alk) is a hydrogen atom or a C₁-C₆ alkyl group and the same shall apply hereinafter.

(Step C1)

In this step, the compound of formula (XVII) is prepared by Michael reaction (C1-a) of the compound of formula (XIV) with the compound of formula (XV), by alkylation reaction (C1-b) of the compound of formula (XIV) with the compound of formula (XVI), or by coupling reaction (C1-c) of the compound of formula (XIV) with the compound of formula (XXIX) followed by the hydrogenation (C1-d). The compound of formula (XIV), (XV), (XVI) and (XXIX) are commercially available.

(C1-a) Michael Reaction

The reaction is normally and preferably effected in the presence or the absence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: ethers, such as diethyl ether diisopropyl ether, tetrahydrofuran and dioxane; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; alcohols, such as methanol, ethanol, propanol, 2-propanol and butanol; nitriles, such as acetonitrile and benzonitrile; sulfoxides, such as dimethyl sulfoxide and sulfolane; or mixed solvents thereof. Of these, the reaction in the absence of solvent is preferred.

The reaction is carried out in the presence of a base. There is likewise no particular restriction on the nature of the bases used, and any base commonly used in reactions of this type may equally be used here. Examples of such bases include: alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal hydrides, such as lithium hydride, sodium hydride and potassium hydride; alkali metal alkoxides, such as sodium methoxide, sodium ethoxide and potassium tert-butoxide; alkali metal carbonates, such as lithium carbonate, sodium carbonate and potassium carbonate: amines, such as N-methylmorpholine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine, dicyclohexylamine, N-methylpiperidine, pyridine, 4-pyrrolidinopyridine, picoline, 4-(N,N-dimethylamino)pyridine, 2,6-di(tert-butyl)-4-methylpyridine, quinoline, N,N-dimethylaniline, N,N-diethylaniline, DBN, DASCO, DBU and benzyltrimethylammonium hydroxide; alkali metal amides, such as lithium amide, sodium amide, potassium amide, lithium diisopropyl amide, potassium diisopropyl amide, sodium diisopropyl amide, lithium bis(trimethylsilyl)amide and potassium bis(trimethylsilyl)amide. Of these, benzyltrimethylammonium hydroxide or sodium methoxide is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 20° C. to about 120° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 60 minutes to about 48 hours, will usually suffice.

After the above procedure, hydrolysis is carried out by adding an acid in a solvent to produce the compound of formula (XIV), and may be carried out in a usual hydrolysis condition. The acid may include, for example, inorganic acids such as hydrochloric acid, hydrobromic acid and sulfuric acid. It is preferably hydrochloric acid. The solvent may include, for example, water; alcohols such as methanol, ethanol, propanol and tert-butanol; ethers such as diethyl ether, dimethoxyethane, tetrahydrofuran, diethoxymethane and dioxane; or mixed solvents thereof. It is preferably water. The reaction temperature varies depending on the starting compound, the reagent and the solvent, however, it is usually from 20° C. to the reflux temperature. The reaction time varies depending on the starting compound, the reagent, the solvent and the reaction temperature, however, it is usually from 60 minutes to 24 hours.

(C1-b) Alkylation Reaction

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; alcohols, such as methanol, ethanol, propanol, 2-propanol and butanol; nitrites, such as acetonitrile and benzonitrile; sulfoxides, such as dimethyl sulfoxide and sulfolane; ketones, such as acetone and diethylketone; water, or mixed solvents thereof. Of these, water is preferred.

The reaction is carried out in the presence of a base. There is likewise no particular restriction on the nature of the bases used, and any base commonly used in reactions of this type may equally be used here. Examples of such bases include: alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal hydrides, such as lithium hydride, sodium hydride and potassium hydride; alkali metal alkoxides, such as sodium methoxide, sodium ethoxide and potassium tert-butoxide; alkali metal carbonates, such as lithium carbonate, sodium carbonate and potassium carbonate; alkali metal amides, such as lithium amide, sodium amide, potassium amide, lithium diisopropyl amide, potassium diisopropyl amide, sodium diisopropyl amide, lithium bis(trimethylsilyl)amide and potassium bis(trimethylsilyl)amide. Of these, sodium hydroxide is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 20° C. to about 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 60 minutes to about 24 hours, will usually suffice.

(C1-c) Coupling Reaction

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; amines, such as N-methylmorpholine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine, N-methylpiperidine, pyridine, 4-pyrrolidinopyridine, N,N-dimethylaniline and N,N-diethylaniline; alcohols, such as methanol, ethanol, propanol, 2-propanol and butanol; nitrites, such as acetonitrile and benzonitrile; sulfoxides, such as dimethyl sulfoxide and sulfolane; and ketones, such as acetone and diethylketone. Of these solvents, acetonitrile and tetrahydrofuran are preferred.

The reaction is carried out in the presence of a base. There is likewise no particular restriction on the nature of the bases used, and any base commonly used in reactions of this type may equally be used here. Examples of such bases include: alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal hydrides, such as lithium hydride, sodium hydride and potassium hydride; alkali metal alkoxides, such as sodium methoxide, sodium ethoxide and potassium t-butoxide; alkali metal carbonates, such as lithium carbonate, sodium carbonate and potassium carbonate; alkali metal hydrogencarbonates, such as lithium hydrogencarbonate, sodium hydrogencarbonate and potassium hydrogencarbonate; amines, such as N-methylmorpholine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine, N-methylpiperidine, pyridine, 4-(N,N-dimethylamino)pyridine and DBU; and tetraalkylammonium fluorides, such as tetra-n-butylammonium fluoride (TBAF). Of these, TBAF is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 5 minutes to about 72 hours will usually suffice.

(C1-d) Hydrogenation

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: aromatic hydrocarbons, such as toluene; alcohols, such as methanol and ethanol; and carboxylic acids, such as acetic acid. Of these solvents, alcohols and carboxylic acids are preferred.

The reaction is carried out under hydrogen atmosphere and in the presence of a catalyst. There is likewise no particular restriction on the nature of the catalysts used, and any catalysts commonly used in reaction of this type may equally be used here. Examples of such catalysts include; palladium on carbon, palladium hydroxide, platinum and Raney nickel. Of these catalysts, palladium on carbon is preferred.

In case that hydrodehalogenation (of substituent “Hal” in Reaction Scheme C) is a serious problem, the reaction may be carried out in the presence of an additive, which reduces activity of the catalyst employed. The additive is selected from substances known to show poisonous effect in some extent against the catalyst. Examples of such additives include: halide ion source, such as tetra-n-butylammonium bromide and sodium bromide; and sulfoxides, such as dimethylsulfoxide. Of these, sodium bromide is preferred.

The reaction can take place under a wide range of pressures, and precise pressure is not critical to the invention. The preferred pressure will depend upon such factors as the nature of the starting materials, and the solvent. However, in general, it is convenient to carry out the reaction at a pressure of from 1 atm to about 10 atm. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 50° C. The time required for the reaction may also vary widely, depending on many factors, notably the pressure of hydrogen, the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred condition outlined above, a period of from about 30 minutes to about 12 hours will usually suffice.

Introduction of the Hydroxy-Protecting Group

In the case of the compound of formula (Xa-1)or(Xb-1) having a hydroxy group, if necessary, the reaction may be accomplished by protecting the hydroxy group.

The introduction of the hydroxy-protecting group can be carried out at an appropriate step before the reaction affected by the hydroxy group.

This reaction is described in detail by T. W. Greene et al., Protective Groups in Organic Synthesis, 369-453, (1999), the disclosures of which are incorporated herein by reference. The following exemplifies a typical reaction involving the protecting group tert-butyldimethylsilyl.

For example, when the hydroxy-protecting group is a “tert-butyldimethylsilyl”, this step is conducted by reacting with a desired hydroxy-protecting group halide in an inert solvent in the presence of a base.

Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; or mixed solvents thereof. Of these, tetrahydrofuran or N,N-dimethylformamide is preferred.

Examples of the hydroxy-protecting group halide usable in the above reaction include trimethylsilyl chloride, triethylsilyl chloride, tert-butyldimethylsilyl chloride, tert-butyidimethylsilyl bromide, acetyl chloride are preferred.

Examples of the base include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, alkali metal carbonates such as lithium carbonate, sodium carbonate and potassium carbonate, and organic amines such as triethylamine, tributylamine, N-methylmorpholine, pyridine, imidazole, 4-dimethylaminopyridine, picoline, lutidine, collidine, DBN and DBU. Out of these, triethylamine, imidazole, or pyridine is preferred. Upon use of an organic amine in the liquid form, it also serves as a solvent when used in large excess.

Although the reaction temperature differs with the nature of the starting compound, the halide and the solvent, it usually ranges from 0° C. to 80° C. (preferably 0 to 30° C.). Although the reaction time differs with the reaction temperature or the like, it ranges from 10 minutes to 2 days (preferably 30 minutes to 1 day).

(Step C2)

In this step, the compound of formula (XVIIIa) is prepared by Friedel Crafts reaction (C2-a) after halogenation (C2-b) or by cyclization (C2-c) of the compound of formula (XVII) when R^(alk) is a hydrogen atom, or by acidic cyclization (C2-d) of the compound of formula (XVII) when R^(alk) is a C₁-C₆ alkyl group.

(C2-a) Friedel Crafts Reaction

The reaction is normally and preferably effected in the presence or the absence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride, 1,1,2,2-tetrachloroehane and 1,2-dichloroethane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; carbon disulfide; or mixed solvents thereof. Of these, dichloromethane or carbon disulfide is preferred.

The reaction is carried out in the presence of an acid. There is likewise no particular restriction on the nature of the acids used, and any acid commonly used in reactions of this type may equally be used here. Examples of such acids include: Lewis acids, such as BF₃, AlCl₃, AlBr₃, FeCl₃, AgCl, ZnI₂, ZnCl₂, Fe(NO₃)₃, CF₃SO₃Si(CH₃)₃, Yb(CF₃SO₃)₃ and SnCl₄. Of these, AlCl₃ is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 150° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 30 minutes to about 24 hours, will usually suffice.

(C2-b) Halogenation

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; amines, such as nitrites, such as acetonitrile and benzonitrile; or mixed solvents thereof. Of these, 1,2-dichloroethane or dichloromethane is preferred.

The reaction is carried out in the presence of a halogenating agent. There is likewise no particular restriction on the nature of the halogenating agents used, and any halogenating agent commonly used in reactions of this type may equally be used here. Examples of such halogenating agents include: thionyl chloride, oxalyl chloride and phosphorus oxychloride. Of these, thionyl chloride is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 80° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 10 minutes to about 8 hours will usually suffice.

(C2-c) Cyclization

The reaction is normally and preferably effected in the presence or absence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; or mixed solvents thereof. Of these, dichloromethane or the absence of solvent is preferred.

The reaction is carried out in the presence of an acid. There is likewise no particular restriction on the nature of the acids used, and any acid commonly used in reactions of this type may equally be used here. Examples of such acids include: acids, such as hydrochloric acid, sulfuric acid, or hydrobromic acid; acids, such as trifluoro acetic acid, or polyphosphoric acid. Of these, polyphosphoric acid is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 20° C. to about 150° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 30 minutes to about 24 hours, will usually suffice.

(C2-d) Acidic Cyclization

The reaction is normally and preferably effected in the presence of an acid, which functions as solvent and reagent. There is no particular restriction on the nature of the acid to be employed, provided that it has no adverse effect on the reaction and that it can dissolve substrate, at least to some extent. Examples of suitable acids include: sulfuric acid and trifluoromethanesulfonic acid. Of these, trifluoromethanesulfonic acid is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 150° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 30 minutes to about 5 hours, will usually suffice,

(Step C3)

In this step, the compound (Xa-1) is prepared by reduction of the carbonyl group of the compound of formula (XVIIIa). In case of employing the optically active reducing agent, the resulting compound of formula (XVIIIa) may be obtained as an optically active compound.

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; sulfoxides, such as dimethyl sulfoxide and sulfolane; alcohols, such as methanol, ethanol, propanol, 2-propanol and butanol; or mixed solvents thereof. Of these, methanol or tetrahydrofuran is preferred.

The reaction is carried out in the presence of a reducing agent. There is likewise no particular restriction on the nature of the reducing agents used, and any reducing agent commonly used in reactions of this type may equally be used here. Examples of such reducing agents include: metal borohydrides, such as sodium borohydride, lithium borohydride and sodium cyanoborohydride; hydride compounds, such as lithium aluminum hydride and diisobutyl aluminum hydride; and borane reagents, such as boran-tetrahydrofuran complex, boran-dimethyl sulfide complex (BMS) and 9-borabicyclo[3,3,1]nonane (9-BBN). Of these, sodium borohydride is preferred.

Concerning an optically active reducing agent, there is likewise no particular restriction on the nature of the reducing agents used, and any reducing agent commonly used in reactions of this type may equally be used here. Examples of such reducing agents include: the combination of (S)or(R)-tetrahydro-1-methyl-3,3-diphenyl-1H,3H-pyrrolo[1,2-c][1,3,2]oxazaborole and BMS; the combination of the optically active ruthenium catalyst and hydrogen gas. Examples of the optically active ruthenium catalyst includes; Dichloro[(S)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl][(S)-1,1′-bis(p-methoxyphenyl)-2-isopropyl-1,2-et hanediamine]ruthenium(II), Dichloro[(R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl][R)-1,1′-bis(p-methoxyphenyl)-2-isopropyl-1,2-et hanediamine]ruthenium(II). The ruthenium catalyst is used in the presence of an catalytic amount of potassium tert-butoxide. Of these, the combination of (S)or(R)-tetrahydro-1-methyl-3,3-diphenyl-1H,3H-pyrrolo[1,2-c][1,3,2]oxazaborole and BMS is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 80° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 10 minutes to about 8 hours will usually suffice.

(Step C4)

In this step, the compound of formula (Xb-1) is prepared by halogenation of the hydroxy group of the compound of formula (Xa-1).

The reaction is normally and preferably effected in the presence or the absence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; amines, such as N-methylmorpholine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine, dicyclohexylamine, N-methylpiperidine, pyridine, 4-pyrrolidinopyridine, N,N-dimethylaniline and N,N-diethylaniline; nitriles, such as acetonitrile and benzonitrile; sulfoxides, such as dimethyl sulfoxide and sulfolane; or mixed solvents thereof. Of these, diethyl ether or tetrahydrofuran is preferred.

The reaction may be carried out in the presence of a base. There is likewise no particular restriction on the nature of the bases used, and any base commonly used in reactions of this type may equally be used here. Examples of such bases include: amines, such as N-methylmorpholine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine, dicyclohexylamine, N-methylpiperidine, pyridine, 4-pyrrolidinopyridine, picoline, 4-(N,N-dimethylamino)pyridine, 2,6-ditert-butyl)-4-methylpyridine, quinoline, N,N-dimethylaniline, N,N-diethylaniline, DBN, DABCO and DBU. Of these, pyridine is preferred.

The reaction is carried out in the presence of a halogenating agent. There is likewise no particular restriction on the nature of the halogenating agents used, and any halogenating agent commonly used in reactions of this type may equally be used here. Examples of such halogenating agents include: thionyl chloride, oxalyl chloride, phosphorus pentachloride and phosphorus oxychloride. Of these, thionyl chloride is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 10 minutes to about 8 hours will usually suffice.

Method D

This illustrates the preparation of compounds of formula (Xa-2) and (Xb-2) wherein B is CH₂.

In Reaction Scheme D, R^(c) and R^(d) independently represent a C₁-C₆ alkyl group.

(Step D1)

In this step, the compound of formula (XX) is prepared by halogenation of the methyl group of the compound of formula (XIX).

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: halogenated hydrocarbons, such as dichloromethane, chloroform, carbon tetrachloride and 1,2-dichloroethane; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; nitrites, such as acetonitrile and benzonitrile; sulfoxides, such as dimethyl sulfoxide and sulfolane; or mixed solvents thereof. Of these, carbon tetrachloride or 1,2-dichloroethane is preferred.

The reaction is carried out in the presence of a halogenating agent. There is likewise no particular restriction on the nature of the halogenating agents used, and any halogenating agent commonly used in reactions of this type may equally be used here. Examples of such halogenating agents include: succinimides, such as N-bromosuccinimide (NBS), N-chlorosuccinimide (NCS); bromine. Of these, NBS is preferred.

Reagents, such as benzoyl peroxide and 2,2′-azobis(isobutyronitrile) (AIBN) may be employed for this step. Of these, benzoyl peroxide is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 100° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 30 minutes to about 24 hours will usually suffice.

(Step D2)

In this step, the compound of formula (XXII) is prepared by ether formation reaction of the compound of formula (XX) with the compound of formula (XXI), which is commercially available.

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; nitriles, such as acetonitrile and benzonitrile; sulfoxides, such as dimethyl sulfoxide and sulfolane; or mixed solvents thereof. Of these, N,N-dimethylformamide or tetrahydrofuran is preferred.

The reaction is carried out in the presence of a base. There is likewise no particular restriction on the nature of the bases used, and any base commonly used in reactions of this type may equally be used here. Examples of such bases include: alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal hydrides, such as lithium hydride, sodium hydride and potassium hydride; alkali metal alkoxides, such as sodium methoxide, sodium ethoxide and potassium tert-butoxide; alkali metal amides, such as lithium amide, sodium amide, potassium amide, lithium diisopropyl amide, potassium diisopropyl amide, sodium diisopropyl amide, lithium bis(trimethylsilyl)amide and potassium bis(trimethylsilyl)amide. Of these, sodium hydride is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 20° C. to about 150° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 60 minutes to about 48 hours, will usually suffice.

(Step D3)

In this step, the compound of formula (XXIII) is prepared by cyclization (Dieckmann Condensation) of the compound of formula (XXII).

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; alcohols, such as methanol, ethanol, propanol, 2-propanol and butanol; or mixed solvents thereof. Of these, toluene is preferred.

The reaction is carried out in the presence of a base. There is likewise no particular restriction on the nature of the bases used, and any base commonly used in reactions of this type may equally be used here. Examples of such bases include: alkali metal, such as lithium and sodium; alkali metal hydrides, such as lithium hydride, sodium hydride and potassium hydride; alkali metal amides, such as lithium amide, sodium amide, potassium amide, lithium diisopropyl amide, potassium diisopropyl amide, sodium diisopropyl amide, lithium bis(trimethylsilyl)amide and potassium bis(trimethylsilyl)amide. Of these, sodium is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 0° C. to about 150° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 30 minutes to about 24 hours, will usually suffice.

(Step D4)

In this step, the compound of formula (XVIIIb) is prepared by decarboxylation of the compound of formula (XXIII).

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; alcohols, such as methanol, ethanol, propanol, 2-propanol, ethylene glycol and butanol; nitrites, such as acetonitrile and benzonitrile; sulfoxides, such as dimethyl sulfoxide and sulfolane; water; or mixed solvents thereof. Of these, ethanol is preferred.

The reaction may be carried out in the presence of a base. There is likewise no particular restriction on the nature of the bases used, and any base commonly used in reactions of this type may equally be used here. Examples of such bases include: alkali metal hydroxides, such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal carbonates, such as lithium carbonate, sodium carbonate and potassium carbonate. Of these, sodium hydroxide is preferred.

The reaction may be carried out in the presence of an acid. There is likewise no particular restriction on the nature of the acids used, and any acid commonly used in reactions of this type may equally be used here. Examples of such acids include: carboxylic acids, such as acetic acid or propionic acid; acids, such as hydrochloric acid, sulfuric acid, or hydrobromic acid. Of these, hydrochloric acid is preferred.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 20° C. to about 120° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 60 minutes to about 48 hours, will usually suffice.

(Step D5)

In this step, the compound of formula (Xa-2) is prepared by reduction of the compound of formula (XVIIIb). The reaction may be carried out under the same condition as described in Step C3 of Method C.

(Step D6)

In this step, the compound of formula (Xb-2) is prepared by halogenation of the compound of formula (Xa-2). The reaction may be carried out under the same condition as described in Step C4 of Method C. If the compound of formula (Xb-2) has hydroxy groups, the reaction for introducing the hydroxy-protecting group described in Method D will be applied in an appropriate step.

(Step D7)

In this step, the compound of formula (XXVI) is prepared by ether formation reaction of the compound of formula (XXIV) with the compound of formula (XXV), which is commercially available. The reaction may be carried out under the same condition as described in Step D2 of Method D.

(Step D8)

In this step, the compound of formula (XXVII) is prepared by hydrolysis of the compound of formula (XXIV). The reaction may be carried out under the same condition as described in Step A4 of Method A.

(Step D9)

In this step, the compound of formula (XVIIIb) is prepared by cyclization (D9-a) of the compound of formula (XXVII) or by formation of acid halide (D9-b) followed by Friedel Crafts reaction (D9-c) of the compound of formula (XXVII). The reaction may be carried out under the same condition as described in Step C2 of Method C.

Method E

This illustrates the preparation of compounds of formula (IX).

In this step, the compound of formula (XXVIII) is prepared by the reduction and cyclization (E1-a) of the compound of formula (IV), which may be prepared by the Step A1 of Method A, followed by the protection of nitrogen atom (E1-b). The reduction and cyclization (E1-a) may be carried out under the same condition as described in Step A3 of Method A and the protection of the nitrogen atom may be carried out under the same condition described in Step A5 of method A.

(Step E2)

In this step, the compound of formula (IX) is prepared by the amidation of the compound of formula (XXVIII) with the compound of formula (VIIII) under the carbon monoxide atmosphere followed by the deprotection of the protecting group 1 (Prot¹). The deprotection of the protecting group (Prot¹) may be carried out under the same condition described in Step A5 of method A.

The reaction is normally and preferably effected in the presence of solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve reagents, at least to some extent. Examples of suitable solvents include: ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as benzene, toluene and nitrobenzene; amides, such as formamide, N,N-dimethylformamide, N,N-dimethylacetamide and hexamethylphosphoric triamide; nitriles, such as acetonitrile and benzonitrile; and ketones, such as acetone and diethylketone. Of these solvents, tetrahydrofuran is preferred.

The reaction is carried out in the presence of a palladium catalyst. There is no particular restriction on the nature of the palladium catalyst to be employed, and any palladium catalyst commonly used in reactions of this type may equally be used here. Examples of such palladium catalysts include: palladium metal, palladium-carbon, palladium (II) acetate, tris(dibenzylideneacetone)dipalladiumchloroform, [1,2-bis(diphenylphosphino)ethane]palladium dichloride, bis(tri-o-toluylphosphine)palladium dichloride, bis(triphenylphosphine)palladium dichloride, tetrakis(triphenylphosphine) palladium, dichloro[1,1′-bis(diphenylphosphino)ferrocene]palladium, or a catalyst produced in solution by adding a ligand into the reaction solution of these. The ligand added into the reaction solution may be a phosphoric ligand such as 1,1′-bis(diphenylphosphino)ferrocene, bis(2-diphenylphosphinophenyl)ether, 2,2′-bis(diphenylphosphino)-1,1′-binaphthol, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, tri-o-toluylphosphine, triphenylphosphine, 2-diphenylphosphino-2′-methoxy-1,1′-binaphthyl or 2,2-bis(diphenylphosphino)-1,1′-binaphthyl. The above palladium catalyst is preferably tetrakis(triphenylphosphine) palladium.

The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. The preferred reaction temperature will depend upon such factors as the nature of the solvent, and the starting materials. However, in general, it is convenient to carry out the reaction at a temperature of from about 20° C. to about 120° C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the starting materials and solvent employed. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from about 60 minutes to about 72 hours, will usually suffice

The compounds of formula (I) and the intermediates in the above-mentioned preparation methods can be isolated and purified by conventional procedures, such as distillation, recrystallization or chromatographic purification.

Compounds of the invention intended for pharmaceutical use may be administered as crystalline or amorphous products. They may be obtained, for example, as solid plugs, powders, or films by methods such as precipitation, crystallization, freeze-drying, spray drying, or evaporative drying. Microwave or radio frequency drying may be used for this purpose.

Conventional techniques for the preparation/isolation of individual enantiomers include chiral synthesis from a suitable optically pure precursor or resolution of the racemate (or the racemate of a salt or derivative) using, for example, chiral high-pressure liquid chromatography (HPLC).

Alternatively, a method of optical resolution of a racemate (or a racemic precursor) can be appropriately selected from conventional procedures, for example, preferential crystallization, or resolution of diastereomeric salts between a basic moiety of the compound of formula (I) and a suitable optically active acid such as tartaric acid.

They may be administered alone or in combination with one or more other compounds of the invention or in combination with one or more other drugs (or as any combination thereof). Generally, they will be administered as a pharmaceutical composition or formulation in association with one or more pharmaceutically acceptable carriers or excipients. The term “carrier” or “excipient” is used herein to describe any ingredient other than the compound(s) of the invention. The choice of carrier or excipient will to a large extent depend on factors such as the particular mode of administration, the effect of the excipient on solubility and stability, and the nature of the dosage form.

Pharmaceutical compositions suitable for the delivery of compounds of the present invention and methods for their preparation will be readily apparent to those skilled in the art. Such compositions and methods for their preparation may be found, for example, in ‘Remington's Pharmaceutical Sciences’, 19th Edition (Mack Publishing Company, 1995).

Oral Administration

The compounds of the invention may be administered orally. Oral administration may involve swallowing, so that the compound enters the gastrointestinal tract, or buccal or sublingual administration may be employed by which the compound enters the blood stream directly from the mouth.

Formulations suitable for oral administration include solid formulations such as, for example, tablets, capsules containing particulates, liquids, or powders, lozenges (including liquid-filled), chews, multi- and nano-particulates, gels, solid solution, liposome, films (including muco-adhesive), ovules, sprays and liquid formulations.

Liquid formulations include, for example, suspensions, solutions, syrups and elixirs. Such formulations may be employed as fillers in soft or hard capsules and typically comprise a carrier, for example, water, ethanol, polyethylene glycol, propylene glycol, methylcellulose, or a suitable oil, and one or more emulsifying agents and/or suspending agents. Liquid formulations may also be prepared by the reconstitution of a solid, for example, from a sachet.

The compounds of the invention may also be used in fast-dissolving, fast-disintegrating dosage forms such as those described in Expert Opinion in Therapeutic Patents, 11 (6), 981-986 by Liang and Chen (2001).

For tablet dosage forms, depending on dose, the drug may make up from about 1 wt % to about 80 wt % of the dosage form, more typically from about 5 wt % to about 60 wt % of the dosage form. In addition to the drug, tablets generally contain a disintegrant. Examples of disintegrants include sodium starch glycolate, sodium carboxymethyl cellulose, calcium carboxymethyl cellulose, croscarmellose sodium, crospovidone, polyvinylpyrrolidone, methyl cellulose, microcrystalline cellulose, lower alkyl-substituted hydroxypropyl cellulose, starch, pregelatinized starch and sodium alginate. Generally, the disintegrant will comprise from about 1 wt % to about 25 wt %, preferably from about 5 wt % to about 20 wt % of the dosage form.

Binders are generally used to impart cohesive qualities to a tablet formulation. Suitable binders include microcrystalline cellulose, gelatin, sugars, polyethylene glycol, natural and synthetic gums, polyvinylpyrrolidone, pregelatinized starch, hydroxypropyl cellulose and hydroxypropyl methylcellulose. Tablets may also contain diluents, such as lactose (monohydrate, spray-dried monohydrate, anhydrous and the like), mannitol, xylitol, dextrose, sucrose, sorbitol, microcrystalline cellulose, starch and dibasic calcium phosphate dihydrate.

Tablets may also optionally comprise surface-active agents, such as sodium lauryl sulfate and polysorbate 80, and glidants such as silicon dioxide and talc. When present, surface active agents may comprise from about 0.2 wt % to about 5 wt % of the tablet, and glidants may comprise from about 0.2 wt % to about 1 wt % of the tablet.

Tablets also generally contain lubricants such as magnesium stearate, calcium stearate, zinc stearate, sodium stearyl fumarate, and mixtures of magnesium stearate with sodium lauryl sulphate. Lubricants generally comprise from about 0.25 wt % to about 10 wt %, preferably from about 0.5 wt % to about 3 wt % of the tablet.

Other possible ingredients include anti-oxidants, colourants, flavouring agents, preservatives and taste-masking agents.

Exemplary tablets contain up to about 80% drug, from about 10 wt % to about 90 wt % binder, from about 0 wt % to about 85 wt % diluent, from about 2 wt % to about 10 wt % disintegrant, and from about 0.25 wt % to about 10 wt % lubricant.

Tablet blends may be compressed directly or by roller to form tablets. Tablet blends or portions of blends may alternatively be wet-, dry-, or melt-granulated, melt congealed, or extruded before tabletting. The final formulation may comprise one or more layers and may be coated or uncoated; it may even be encapsulated.

The formulation of tablets is discussed in “Pharmaceutical Dosage Forms: Tablets, Vol. 1”, by H. Lieberman and L. Lachman, Marcel Dekker, N.Y., N.Y., 1980 (ISBN 0-8247-6918-X).

Solid formulations for oral administration may be formulated to be immediate and/or modified release. Modified release formulations include delayed-, sustained-, pulsed-, controlled-, targeted and programmed release.

Suitable modified release formulations for the purposes of the invention are described in U.S. Pat. No. 6,106,864. Details of other suitable release technologies such as high energy dispersions and osmotic and coated particles are to be found in Verma et al, Pharmaceutical Technology On-line, 25(2), 1-14 (2001). The use of chewing gum to achieve controlled release is described in WO 00/35298.

Parenteral Administration

The compounds of the invention may also be administered directly into the blood stream, into muscle, or into an internal organ. Suitable means for parenteral administration include intravenous, intraarterial, intraperitoneal, intrathecal, intraventricular, intraurethral, intrasternal, intracranial, intramuscular and subcutaneous. Suitable devices for parenteral administration include needle (including microneedle) injectors, needle-free injectors and infusion techniques.

Parenteral formulations are typically aqueous solutions which may contain excipients such as salts, carbohydrates and buffering agents (preferably to a pH of from about 3 to about 9), but, for some applications, they may be more suitably formulated as a sterile non-aqueous solution or as a dried form to be used in conjunction with a suitable vehicle such as sterile, pyrogen-free water.

The preparation of parenteral formulations under sterile conditions, for example, by lyophilization, may readily be accomplished using standard pharmaceutical techniques well known to those skilled in the art.

The solubility of compounds of formula (I) used in the preparation of parenteral solutions may be increased by the use of appropriate formulation techniques, such as the incorporation of solubility-enhancing agents.

Formulations for parenteral administration may be formulated to be immediate and/or modified release. Modified release formulations include delayed-, sustained-, pulsed-, controlled-, targeted and programmed release. Thus compounds of the invention may be formulated as a solid, semi-solid, or thixotropic liquid for administration as an implanted depot providing modified release of the active compound. Examples of such formulations include drug-coated stents and PGLA microspheres.

Topical Administration

The compounds of the invention may also be administered topically to the skin or mucosa, that is, dermally or transdermally. Typical formulations for this purpose include gels, hydrogels, lotions, solutions, creams, ointments, dusting powders, dressings, foams, films, skin patches, wafers, implants, sponges, fibres, bandages and microemulsions. Liposomes may also be used. Typical carriers include alcohol, water, mineral oil, liquid petrolatum, white petrolatum, glycerin, polyethylene glycol and propylene glycol. Penetration enhancers may be incorporated—see, for example, J Pharm Sci, 88 (10), 955-958 by Finnin and Morgan (October 1999).

Other means of topical administration include delivery by electroporation, iontophoresis, phonophoresis, sonophoresis and microneedle or needle-free (e.g. Powderject™, Bioject™, etc.) injection.

Formulations for topical administration may be formulated to be immediate and/or modified release. Modified release formulations include delayed-, sustained-, pulsed-, controlled-, targeted and programmed release.

Inhaled/Intranasal Administration

The compounds of the invention can also be administered intranasally or by inhalation, typically in the form of a dry powder (either alone, as a mixture, for example, in a dry blend with lactose, or as a mixed component particle, for example, mixed with phospholipids, such as phosphatidylcholine) from a dry powder inhaler or as an aerosol spray from a pressurized container, pump, spray, atomiser (preferably an atomiser using electrohydrodynamics to produce a fine mist), or nebuliser, with or without the use of a suitable propellant, such as 1,1,1,2-tetrafluoroethane or 1,1,1,2,3,3,3-heptafluoropropane. For intranasal use, the powder may comprise a bioadhesive agent, for example, chitosan or cyclodextrin.

The pressurized container, pump, spray, atomizer, or nebuliser contains a solution or suspension of the compound(s) of the invention comprising, for example, ethanol, aqueous ethanol, or a suitable alternative agent for dispersing, solubilising, or extending release of the active, a propellant(s) as solvent and an optional surfactant, such as sorbitan trioleate, oleic acid, or an oligolactic acid.

Prior to use in a dry powder or suspension formulation, the drug product is micronised to a size suitable for delivery by inhalation (typically less than 5 microns). This may be achieved by any appropriate comminuting method, such as spiral jet milling, fluid bed jet milling, supercritical fluid processing to form nanoparticles, high pressure homogenization, or spray drying.

Capsules (made, for example, from gelatin or HPMC), blisters and cartridges for use in an inhaler or insufflator may be formulated to contain a powder mix of the compound of the invention, a suitable powder base such as lactose or starch and a performance modifier such as l-leucine, mannitol, or magnesium stearate. The lactose may be anhydrous or in the form of the monohydrate, preferably the latter. Other suitable excipients include dextran, glucose, maltose, sorbitol, xylitol, fructose, sucrose and trehalose.

A suitable solution formulation for use in an atomizer using electrohydrodynamics to produce a fine mist may contain from about 1 μg to about 20 mg of the compound of the invention per actuation and the actuation volume may vary from about 1 μl to about 100 μl. A typical formulation may comprise a compound of formula (I), propylene glycol, sterile water, ethanol and sodium chloride. Alternative solvents which may be used instead of propylene glycol include glycerol and polyethylene glycol.

Suitable flavours, such as menthol and levomenthol, or sweeteners, such as saccharin or saccharin sodium, may be added to those formulations of the invention intended for inhaled/intranasal administration. Formulations for inhaled/intranasal administration may be formulated to be immediate and/or modified release using, for example, poly(DL-lactic-coglycolic acid) (PGLA). Modified release formulations include delayed-, sustained-, pulsed-, controlled-, targeted and programmed release.

In the case of dry powder inhalers and aerosols, the dosage unit is determined by means of a valve which delivers a metered amount. Units in accordance with the invention are typically arranged to administer a metered dose or “puff” containing from about 1 to about 100 μg of the compound of formula (I). The overall daily dose will typically be in the range about 50 μg to about 20 mg which may be administered in a single dose or, more usually, as divided doses throughout the day.

Rectal/Intravaginal Administration

The compounds of the invention may be administered rectally or vaginally, for example, in the form of a suppository, pessary, or enema. Cocoa butter is a traditional suppository base, but various alternatives may be used as appropriate.

Formulations for rectal/vaginal administration may be formulated to be immediate and/or modified release. Modified release formulations include delayed-, sustained-, pulsed-, controlled-, targeted and programmed release.

Other Technologies

The compounds of the invention may be combined with soluble macromolecular entities, such as cyclodextrin and suitable derivatives thereof or polyethylene glycol-containing polymers, in order to improve their solubility, dissolution rate, taste-masking, bioavailability and/or stability for use in any of the aforementioned modes of administration.

Drug-cyclodextrin complexes, for example, are found to be generally useful for most dosage forms and administration routes. Both inclusion and non-inclusion complexes may be used. As an alternative to direct complexation with the drug, the cyclodextrin may be used as an auxiliary additive, i.e. as a carrier, diluent, or solubiliser. Most commonly used for these purposes are alpha-, beta- and gamma-cyclodextrins, examples of which may be found in. WO 91/11172, WO 94/02518 and WO 98/55148.

Kit-of-Parts

Inasmuch as it may be desirable to administer a combination of active compounds, for example, for the purpose of treating a particular disease or condition, it is within the scope of the present invention that two or more pharmaceutical compositions, at least one of which contains a compound in accordance with the invention, may conveniently be combined in the form of a kit suitable for coadministration of the compositions.

Thus the kit of the invention comprises two or more separate pharmaceutical compositions, at least one of which contains a compound of formula (I) in accordance with the invention, and means for separately retaining said compositions, such as a container, divided bottle, or divided foil packet. An example of such a kit is the familiar blister pack used for the packaging of tablets, capsules and the like.

The kit of the invention is particularly suitable for administering different dosage forms, for example, oral and parenteral, for administering the separate compositions at different dosage intervals, or for titrating the separate compositions against one another. To assist compliance, the kit typically comprises directions for administration and may be provided with a so-called memory aid.

Dosage

For administration to human patients, the total daily dose of the compounds of the invention is typically in the range of about 0.5 mg to about 300 mg depending, of course, on the mode of administration, preferred in the range of about 1 mg to about 100 mg and more preferred in the range of about 1 mg to about 20 mg. For example, oral administration may require a total daily dose of from about 1 mg to about 20 mg, while an intravenous dose may only require from about 0.5 mg to about 10 mg. The total daily dose may be administered in single or divided doses.

These dosages are based on an average human subject having a weight of about 65 kg to about 70 kg. The physician will readily be able to determine doses for subjects whose weight falls outside this range, such as infants and the elderly.

Combinations

As discussed above, a compound of the invention exhibits acid pump inhibitory activity. An acid pump antagonist of the present invention may be usefully combined with another pharmacologically active compound, or with two or more other pharmacologically active compounds, particularly in the treatment of gastroesophageal reflux disease. For example, an acid pump antagonist, particularly a compound of the formula (I), or a pharmaceutically acceptable salt thereof, as defined above, may be administered simultaneously, sequentially or separately in combination with one or more agents selected from:

-   (i) histamine H₂ receptor antagonists, e.g. ranitidine, lafutidine,     nizatidine, cimetidine, famotidine and roxatidine; -   (ii) proton pump inhibitors, e.g. omeprazole, esomeprazole,     pantoprazole, rabeprazole, tenatoprazole, ilaprazole and     lansoprazole; -   (iii) oral antacid mixtures, e.g. Maalox®, Aludrox® and Gaviscon®; -   (iv) mucosal protective agents, e.g. polaprezinc, ecabet sodium,     rebamipide, teprenone, cetraxate, sucralfate, chloropylline-copper     and plaunotol; -   (v) anti-gastric agents, e.g. Anti-gastrin vaccine, itriglumide and     Z-360; -   (vi) 5-HT₃ antagonists, e.g. dolasetron, palonosetron, alosetron,     azasetron, ramosetron, mitrazapine, granisetron, tropisetron,     E-3620, ondansetron and indisetron; -   (vii) 5-HT₄ agonists, e.g. tegaserod, mosapride, cinitapride and     oxtriptane; -   (viii) laxatives, e.g. Trifyba®, Fybogel®, Konsyl®, Isogel®,     Regulan®, Celevac® and Normacol® -   (ix) GABA_(B) agonists, e.g. baclofen and AZD-3355; -   (x) GABA_(B) antagonists, e.g. GAS-360 and SGS-742; -   (xi) calcium channel blockers, e.g. aranidipine, lacidipine,     falodipine, azelnidipine, clinidipine, lomerizine, diltiazem,     gallopamil, efonidipine, nisoldipine, amlodipine, lercanidipine,     bevantolol, nicardipine, isradipine, benidipine, verapamil,     nitrendipine, barnidipine, propafenone, manidipine, bepridil,     nifedipine, nilvadipine, nimodipine and fasudil; -   (xii) dopamine antagonists, e.g. metoclopramide, domperidone and     levosulpiride; -   (xiii) Tachykinin (NK) antagonists, particularly NK-3, NK-2 and NK-1     antagonists, e.g. nepadutant, saredutant, talnetant,     (αR,9R)-7-[3,5-bis(trifluoromethyl)benzyl]-8,9,10,11-tetrahydro-9-methyl-5-(4-methylphenyl)-7H-[1,4]diazocino[2,1-g][1,7]naphthridine-6-13-dione     (TAK-637),     5-[[(2R,3S)-2-[(1R)-1-[3,5-bis(trifluoromethyl)phenyl]ethoxy-3-(4-fluorophenyl)-4-morpholinyl]methyl]-1,2-dihydro-3H-1,2,4-triazol-3-one     (MK-869), lanepitant, dapitant and     3-[[2-methoxy-5-(trifluoromethoxy)phenyl]methylamino]-2-phenyl-piperidine     (2S,3S); -   (xiv) Helicobacter pylori infection agents, e.g. clarithromicyn,     roxithromycin, rokitamycin, flurithromycin, telithromycin,     amoxicillin, ampicillin, temocillin, bacampicillin, aspoxicillin,     sultamicillin, piperacillin, lenampicillin, tetracycline,     metronidazole, bithmuth citrate and bithmuth subsalicylate; -   (xv) nitric oxide synthase inhibitors, e.g. GW-274150, tilarginine,     P54, guanidioethyldisulfide and nitroflurbiprofen; -   (xvi) vanilloid receptor 1 antagonists, e.g. AMG-517 and GW-705498; -   (xvii) muscarinic receptor antagonists, e.g. trospium, solifenacin,     tolterodine, tiotropium, cimetropium, oxitropium, ipratropium,     tiquizium, dalifenacin and imidafenacin; -   (xviii) calmodulin antagonists, e.g. squalamine and DY-9760; -   (xix) potassium channel agonists, e.g. pinacidil, tilisolol,     nicorandil, NS-8 and retigabine; -   (xx) beta-1 agonists, e.g. dobutamine, denopamine, xamoterol,     denopamine, docarpamine and xamoterol; -   (xxi) beta-2 agonists, e.g. salbutamol; terbutaline, arformoterol,     meluadrine, mabuterol, ritodrine, fenoterol, clenbuterol,     formoterol, procaterol, tulobuterol, pirbuterol, bambuterol,     tulobuterol, dopexamine and levosalbutamol; -   (xxii) beta agonists, e.g. isoproterenol and terbutaline; -   (xxiii) alpha 2 agonists, e.g. clonidine, medetomidine, lofexidine,     moxonidine, tizanidine, guanfacine, guanabenz, talipexole and     dexmedetomidine; -   (xxiv) endthelin A antagonists, e.g. bonsetan, atrasentan,     ambrisentan, clazosentan, sitaxsentan, fandosentan and darusentan; -   (xxv) opioid μ agonists, e.g. morphine, fentanyl and loperamide; -   (xxvi) opioid μ antagonists, e.g. naloxone, buprenorphine and     alvimopan; -   (xxvii) motilin agonists, e.g. erythromycin, mitemcinal, SLV-305 and     atilmotin; -   (xxviii) ghrelin agonists, e.g. capromorelin and TZP-101; -   (xxix) AchE release stimulants, e.g. Z-338 and KW-5092; -   (xxx) CCK-B antagonists, e.g. itrigiumide, YF-476 and S-0509; -   (xxxi) glucagon antagonists, e.g. NN-2501 and A-770077; -   (xxxii) piperacillin, lenampicillin, tetracycline, metronidazole,     bithmuth citrate and bithmuth subsalicylate; -   (xxxiii) Glucagon-like peptide-1 (GLP-1) antagonists, e.g.     PNU-126814; -   (xxxiv) small conductance calcium-activated potassium channel 3     (SK-3) antagonists, e.g. apamin, dequalinium, atracurium,     pancuronium and tubocurarine -   (xxxv) mGluR5 anatagonists, e.g. ADX-10059 and AFQ-056; -   (xxxvi) 5-HT3 agonists, e.g. pumosetrag(DDP733); -   (xxxvii) mGluR8 agonists, e.g. (S)-3,4-DCPG and mGluR8-A.     Method for Assessing Biological Activities:

The acid pump inhibitory activity and other biological activities of the compounds of this invention were determined by the following procedures. Symbols have their usual meanings in the specification: mL (milliliter(s)), μL (microlitter(s)), Kg (kirogram(s)), g (gram(s)), mg (milligram(s)), μg (microgram(s)), pmol (pico molar(s)), mmol (milli molar(s)), M (molar mass (m³/mol)), mM (milli molar mass), μM (micro molar mass), atm (standard atmospheric pressure), r.p.m. (revolutions pre minute), quant. (quantitative yield), nm (nanometer(s)), min (minute(s)), Cat# (catalog number).

Preparation of Gastric Vesicles from Fresh Porcine Stomachs

The porcine gastric vesicles for Porcine gastric H⁺/K⁺-ATPase inhibition assays were prepared from mucous membrane in fresh porcine stomachs by homogenization with a tight-fitted polytetrafluoroethylene (Teflone®) homogenizer in 0.25 M sucrose at 4° C. The crude pellet was removed with centrifugation at 20,000 g for 30 min. Then supernatant was centrifuged at 100,000 g for 30 min. The resulting pellet was re-suspended in 0.25 M sucrose, and then subjected to density gradient centrifugation at 132,000 g for 90 min. The gastric vesicles were collected from interface on 0.25 M sucrose layer containing 7% Ficoll™ PM400(Amersham Biosciences). This procedure was performed in a cold room.

Ion-Leaky Porcine Gastric H⁺/K⁺-ATPase Inhibition

Ion-leaky porcine gastric H⁺/K⁺-ATPase inhibition was measured according to the modified method described in Biochemical Pharmacology, 1988, 37, 2231-2236.

The isolated vesicles were lyophilized, and then kept in deep-freezer until use. For enzyme assay, lyophilized vesicles were reconstituted with 3 mM MgSO₄ containing 40 mM Bis-tris (pH 6.4 at 37° C.).

Enzyme reaction was performed incubating 5 mM KCl, 3 mM Na₂ATP, 3 mM MgSO₄ and 1.0 μg of reconstituted vesicles for 30 minutes at 37° C. in a final 60 μl of reaction mixture (40 mM Bis-tris, pH 6.4) with or without the test compound. Enzyme reaction was stopped by adding 10% sodium dodecyl sulphate (SDS). Released inorganic phosphate from ATP was detected by incubation with mixture of 1 part of 35 mM ammonium molybdate tetrahydrate in 15 mM Zinc acetate hydrate and 4 parts of 10% ascorbic acid (pH 5.0), resulting in phosphomolybdate, which has optical density at 750 nm.

Ion-Tight Porcine Gastric H⁺/K⁺-ATPase Inhibition

Ion-tight porcine gastric H⁺/K⁺-ATPase inhibition was measured according to the modified method described in Biochemical Pharmacology, 1988, 37, 2231-2236.

The isolated vesicles were kept in deep-freezer until use. For enzyme assay, vesicles were diluted with 3 mM MgSO₄ containing 5 mM Tris (pH 7.4 at 37° C.).

Enzyme reaction was performed incubating 150 mM KCl, 3 mM Na₂ATP, 3 mM MgSO₄ 15 μM valinomycin and 3.0 μg of vesicles for 30 minutes at 37° C. in a final 60 μl of reaction mixture (5 mM Tris, pH 7.4) with or without the test compound. Enzyme reaction was stopped by adding 10% SDS. Released inorganic phosphate from ATP was detected by incubating with mixture of 1 part of 35 mM ammonium molybdate tetrahydrate in 15 mM Zinc acetate hydrate and 4 parts of 10% ascorbic acid (pH 5.0), resulting in phosphomolybdate, which has optical density at 750 nm. The results of IC₅₀ values of the inhibition activity for the compounds of Examples are shown in Table 1.

TABLE 1 Example No. IC₅₀ (μM) 1 0.19 2 0.086 3 0.098 4 0.058 5 0.032 6 0.030 7 1.1 8 0.61 9 0.13 10 0.14 11 0.12 12 0.23 13 0.13 14 0.22 15 0.21 16 0.068 17 0.099 18 0.13 19 0.24 20 0.071 21 0.082 22 0.57 23 0.11 24 0.37 25 0.16 Canine Kidney Na⁺/K⁺-ATPase Inhibition

The powdered canine kidney Na⁺/K⁺-ATPase (Sigma) was reconstituted with 3 mM MgSO₄ containing 40 mM Tris (pH 7.4 at 37° C.). Enzyme reaction was performed incubating 100 mM NaCl, 2 mM KCl, 3 mM Na₂ATP, 3 mM MgSO₄ and 12 μg of enzyme for 30 minutes at 37° C. in a final 60 μl of reaction mixture (40 mM Tris, pH 7.4) with or without the test compound. Enzyme reaction was stopped by adding 10% SDS. Released inorganic phosphate from ATP was detected by incubating with mixture of 1 part of 35 mM ammonium molybdate tetrahydrate in 15 mM Zinc acetate hydrate and 4 parts of 10% ascorbic acid (pH 5.0), resulting in phosphomolybdate, which has optical density at 750 nm.

Inhibition of Acid Secretion in the Gastric Lumen-Perfused Rat

Acid secretion in the gastric lumen-perfused rat was measured according to Watanabe et al. [Watanabe K et al., J. Physiol. (Paris) 2000; 94: 111-116].

Male Sprague-Dawley rats, 8 weeks old, deprived of food for 18 hours before the experiment with free access to water, were anesthetized with urethane (1.4 g/kg, i.p.) and tracheotomized. After a middle abdominal incision, a dual polyethylene cannula was inserted into the forestomach and the stomach was perfused with saline (37° C., pH 5.0) at a rate of 1 ml/min. The acid output in the perfusate was determined at 5 minutes interval by titration with 0.02 M NaOH to pH 5.0. After the determination of basal acid secretion for 30 min, the acid secretion was stimulated by a continuous intravenous infusion of pentagastrin (16 μg/kg/h). The test compounds were administered by an intravenous bolus injection or intraduodenal administration after the stimulated acid secretion reached a plateau phase. The acid secretion was monitored after the administration.

The activity was evaluated either inhibition of total acid secretion from 0 hours to 1.5 or 3.5 hours after administration or the maximum inhibition after administration.

Inhibition of Gastric Acid Secretion in the Heidenhain Pouch Dog

Male Beagle dogs weighing 7-15 kg with Heidenhain pouch [Heidenhain R: Arch Ges Physiol. 1879, 19: 148-167] were used. The animals were allowed to recover from surgery for at least three weeks before the experiments. The animals were kept at a 12 hour light-dark rhythm, housed singly. They received standard food once daily at 11:00 a.m. and tap water ad libitum, and were fasted overnight prior to the experiment, with free access to water. Gastric juice samples were collected throughout the experiment by gravity drainage every 15 min. Acidity in the gastric juice was measured by titration to the end point of pH 7.0. Acid secretion was stimulated by a continuous intravenous infusion of histamine (80 μg/kg/h). Oral or intravenous bolus administration of the test compounds was done 90 minutes after commencement of the histamine infusion. The acid secretion was monitored after the administration. The activity was evaluated by the maximum inhibition relative to the corresponding control value.

The compound of Example 2 showed a good inhibitory activity.

Human Dofetilide Binding

Human ether a-go-go related gene (HERG) transfected HEK293S cells were prepared and grown in-house. Cell paste of HEK-293 cells expressing the HERG product can be suspended in 10-fold volume of 50 mM Tris buffer adjusted at pH 7.5 at 25° C. with 2 M HCl containing 1 mM MgCl₂, 10 mM KCl. The cells were homogenized using a Polytron homogenizer (at the maximum power for 20 seconds) and centrifuged at 48,000 g for 20 minutes at 4° C. The pellet was resuspended, homogenized and centrifuged once more in the same manner. The resultant supernatant was discarded and the final pellet was resuspended (10-fold volume of 50 mM Tris buffer) and homogenized at the maximum power for 20 seconds. The membrane homogenate was aliquoted and stored at −80° C. until use. An aliquot was used for protein concentration determination using a Protein Assay Rapid Kit (wako) and Spectra max plate reader (Wallac). All the manipulation, stock solution and equipment were kept on ice at all times. For saturation assays, experiments were conducted in a total volume of 200 μl. Saturation was determined by incubating 36 μl of [₃H]-dofetilide, and 160 μl of membrane homogenates (20-30 μg protein per well) for 60 minutes at room temperature in the absence or presence of 10 μM dofetilide at final concentrations (4 μl) for total or nonspecific binding, respectively. All incubations were terminated by rapid vacuum filtration over PEI soaked glass fiber filter papers using Skatron cell harvester followed by two washes with 50 mM Tris buffer (pH 7.4 at 25° C.). Receptor-bound radioactivity was quantified by liquid scintillation counting using Packard LS counter.

For the competition assay, compounds were diluted in 96 well polypropylene plates as 4-point dilutions in semi-log format. All dilutions were performed in DMSO first and then transferred into 50 mM Tris buffer (pH 7.4 at 25° C.) containing 1 mM MgCl₂, 10 mM KCl so that the final DMSO concentration became equal to 1%. Compounds were dispensed in triplicate in assay plates (4 μl). Total binding and nonspecific binding wells were set up in 6 wells as vehicle and 10 μM dofetilide at final concentration, respectively. The radioligand was prepared at 5.6× final concentration and this solution was added to each well (36 μl). The assay was initiated by addition of YSi poly-L-lysine SPA beads (50 μl, 1 mg/well) and membranes (110 μl, 20 μg/well). Incubation was continued for 60 minutes at room temperature. Plates were incubated for a further 3 hours at room temperature for beads to settle. Receptor-bound radioactivity was quantified by counting Wallac MicroBeta plate counter.

Caco-2 Permeability

Caco-2 permeability was measured according to the method described in Shiyin Yee, Pharmaceutical Research, 763 (1997).

Caco-2 cells were grown on filter supports (Falcon HTS multiwell insert system) for 14 days. Culture medium was removed from both the apical and basolateral compartments and the monolayers were preincubated with pre-warmed 0.3 ml apical buffer and 1.0 ml basolateral buffer for 0.5 hour at 37° C. in a shaker water bath at 50 cycles/min. The apical buffer consisted of Hanks Balanced Salt Solution, 25 mM D-glucose monohydrate, 20 mM 2-morpholinoethanesulphonic acid (MES) Biological Buffer, 1.25 mM CaCl₂ and 0.5 mM MgCl₂ (pH 6.5). The basolateral buffer consisted of Hanks Balanced Salt Solution, 25 mM D-glucose monohydrate, 20 mM 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid (HEPES) Biological Buffer, 1.25 mM CaCl₂ and 0.5 mM MgCl₂ (pH 7.4). At the end of the preincubation, the media was removed and test compound solution (10 μM) in buffer was added to the apical compartment. The inserts were moved to wells containing fresh basolateral buffer at 1 hour. Drug concentration in the buffer was measured by LC/MS analysis.

Flux rate (F, mass/time) was calculated from the slope of cumulative appearance of substrate on the receiver side and apparent permeability coefficient (P_(app)) was calculated from the following equation. P _(app)(cm/sec)=(F×VD)/(SA×MD)

where SA is surface area for transport (0.3 cm²), VD is the donor volume (0.3 ml), MD is the total amount of drug on the donor side at t=0. All data represent the mean of 2 inserts. Monolayer integrity was determined by Lucifer Yellow transport.

Half-Life in Human Liver Microsomes (HLM)-1

Test compounds (1 μM) were incubated with 3.3 mM MgCl₂ and 0.78 mg/mL HLM (HL101) in 100 mM potassium phosphate buffer (pH 7.4) at 37° C. on the 96-deep well plate. The reaction mixture was split into two groups, a non-P450 and a P450 group. NADPH was only added to the reaction mixture of the P450 group. An aliquot of samples of P450 group was collected at 0, 10, 30, and 60 minutes time point, where 0 minutes time point indicated the time when NADPH was added into the reaction mixture of P450 group. An aliquot of samples of non-P450 group was collected at −10 and 65 minutes time point. Collected aliquots were extracted with acetonitrile solution containing an internal standard. The precipitated protein was spun down in centrifuge (2000 rpm, 15 min). The compound concentration in supernatant was measured by LC/MS/MS system.

The half-life value was obtained by plotting the natural logarithm of the peak area ratio of compounds/internal standard versus time. The slope of the line of best fit through the points yields the rate of metabolism (k). This was converted to a half-life value using following equations: Half-life=ln 2/k Half-Life in Human Liver Microsomes (HLM)-2

Test compounds (1 μM) were incubated with 1 mM MgCl₂, 1 mM NADP+, 5 mM isocitric acid, 1 U/mL isocitric dehydrogenase and 0.8 mg/mL HLM in 100 mM potassium phosphate buffer (pH 7.4) at 37° C. on a number of 384-well plates. At several time points, a plate was removed from the incubator and the reaction was terminated with two incubation volumes of acetonitrile. The compound concentration in supernatant was measured by LC/MS/MS system. The intrinsic clearance value was calculated using following equations.

${{Cl}_{Int}\left( {{ul}\text{/}\min\text{/}{mg}\mspace{14mu}{protein}} \right)} = \frac{k \times {incubation}\mspace{14mu}{volume}}{{Protein}\mspace{14mu}{concentration}}$ Where, k=−slope of ln(concentration) vs. time (min-1) In Vitro Drug-Drug Interaction Studies for Five Major CYPs (fDDI) CYP1A2 Test compounds (3 μM) were pre-incubated with recombinant CYP1A2 (Baculosome lot#21198 Invitrogen, 50 pmol P450/ml) in 100 mM K⁺Phosphate Buffer (pH 7.4) and 10 μM Vivid blue 1A2 probe (Invitrogen) as a substrate for 5 minutes at 30° C. Reaction was initiated by adding a solution of a warmed NADPH-regenerating system A, which consists of 0.50 mM NADP and 10 mM MgCl₂, 6.2 mM DL-Isocitric acid and 0.5 U/ml Isocitric Dehydrogenase (ICD). Plates were placed in the plate reader at 30° C. and were taken readings every 1.5 minutes, with a 10 second shake in between each reading for 15 cycles. Wavelengths of excitation/emission were 408/465 nm, respectively. CYP2C9 Test compounds (3 μM) were pre-incubated with recombinant CYP2C9 (Baculosome lot#20967 Invitrogen, 50 pmol P450/ml) in 100 mM K⁺Phosphate Buffer (pH 7.4) and 30 μM MFC probe (Gentest) as a substrate for 5 minutes at 37° C. Reaction was initiated by adding a solution of the warmed NADPH-regenerating system A. Plates were placed in the plate reader at 37° C. and were taken readings every 2.0 minutes, with a 10 second shake in between each reading for 15 cycles. Wavelengths of excitation/emission were 408/535 nm, respectively. CYP2C19 Test compounds (3 μM) were pre-incubated with recombinant CYP2C19 (Baculosome lot#20795 Invitrogen, 50 pmol P450/ml) in 100 mM K⁺ Phosphate Buffer (pH 7.4) and 10 μM Vivid blue 2019 probe (Invitrogen) as a substrate for 5 minutes at 37° C. Reaction was initiated by adding a solution of the warmed NADPH-regenerating system A. Plates were placed in the plate reader at 37° C. and were taken readings every 1.5 minutes with a 10 second shake in between each reading for 15 cycles. Wavelengths of excitation/emission were 408/465 nm, respectively. CYP2D6 Test compounds (3 μM) were pre-incubated with recombinant CYP2D6 (Baculosome lot#21248 Invitrogen, 20 pmol P450/ml) in 100 mM K⁺Phosphate Buffer (pH 7.4) and 1 μM 3-[2-(N,N-diethyl-N-methylammonium)ethyl]-7-methoxy-4-methylcoumarin (AMMC) probe (Gentest) as a substrate for 5 minutes at 37° C. Reaction was initiated by adding a solution of a warmed NADPH-regenerating system B, which consists of 0.03 mM NADP and 10 mM MgCl₂, 6.2 mM DL-Isocitric acid and 0.5 U/ml ICD. Plates were placed in the plate reader at 37° C. and were taken readings every 2.0 minutes with a 10 second shake in between each reading for 15 cycles. Wavelengths of excitation/emission were 400/465 nm, respectively. CYP3A4 Test compounds (3 μM) were pre-incubated with recombinant CYP3A4 (Baculosome lot#20814 Invitrogen, 5 pmol P450/ml) in 100 mM K⁺Phosphate Buffer (pH 7.4) and 2 μM Vivid Red probe (Invitrogen) as a substrate for 5 minutes at 30° C. Reaction was initiated by adding a solution of the warmed NADPH-regenerating system A. Plates were placed in the plate reader at 30° C. and were taken readings minimum intervals with a 10 second shake in between each reading for 15 cycles. Wavelengths of excitation/emission were 530/595 nm, respectively. Drug-drug interaction was evaluated by the rate of metabolite formation calculated with a slope (Time vs. Fluorescence units) in the linear region or the percentage of inhibition by test compounds calculated by the following equation. Inhibition%={(v _(o) −v _(i))/v _(o)}×100, wherein v_(o) is a rate of control reaction (no test compounds) and v_(i) is a rate of reaction in the presence of test compound. I_(HERG) Assay

Human ether a-go-go related gene (HERG) transfected HEK293 cells are prepared and cultured in-house. The methodology for stable transfection of this channel in HEK cells can be found elsewhere (Z. Zhou et al., 1998, Biophysical journal, 74, 230-241). On the day of experimentation, the cells are harvested from culture flasks and stored as cell suspension in a standard external solution (see below of its composition). in the room atmosphere of 23° C. Cells are studied between 0.5-5 hours after harvest.

HERG currents are studied using a standard patch clamp technique of the whole-cell mode. During the experiment, the cells are superfused with a standard external solution of the following composition; (mM) NaCl, 130; KCl, 4; CaCl₂, 2; MgCl₂, 1; Glucose, 10; HEPES, 5; pH 7.4 with NaOH. Whole-cell recordings is made using a patch clamp amplifier and patch pipettes which have a resistance of 1-3 MOhm when filled with the standard internal solution of the following composition; (mM); KCl, 130; MgATP, 5; MgCl₂, 1; HEPES, 10; EGTA 5, pH 7.2 with KOH. Only those cells with access resistances below 10 MOhm and seal resistances over 1 GOhm are accepted for further experimentation. Series resistance compensation is applied up to a maximum of 80% without any leak subtraction. Following the achievement of whole cell configuration and sufficient time for cell dialysis with pipette solution (>5 min), the membrane is depolarized from a holding potential of −80 mV to +30 mV for 1000 ms followed by a descending voltage ramp (rate 0.5 mV msec⁻¹) back to the holding potential. This depolarization and ramp is applied to the cells continuously every 4 seconds (0.25 Hz). The amplitude of the peak current elicited around −40 mV during the ramp is measured. Once stable evoked current responses of minimal changes in the amplitude are obtained in the external solution, the test compound is applied for 10-20 minutes with multiple dosing in a single cell. The cells are also exposed to high dose of dofetilide (5 μM), a specific IKr blocker, to evaluate the insensitive endogenous current.

All experiments are performed at 23+/−1° C. Evoked membrane currents are recorded online on a computer, filtered at 500-1000 Hz (Bessel −3 dB) and sampled at 1-2 KHz. Osmolarity and pH change induced by the test compound in external solution will be examined at the highest concentration.

The arithmetic mean of these ten values of peak current is calculated under control conditions and in the presence of drug. Percent decrease of I_(N) in each experiment is obtained by the normalized current value using the following formula: I_(N)=(I_(C)−I_(D))/(I_(C)−I_(dof))×100, where I_(C) is the mean current value under control conditions, I_(D) is the mean current value in the presence of test compound and I_(dof) is the mean current value in dofetilide application. Separate experiments are performed and pooled data of arithmetic mean from each experiment is defined as the result of the study.

Bioavailability in Rat

Adult rats of the Sprague-Dawley strain were used. One to two days prior to the experiments all rats were prepared by cannulation of the right jugular vein under anesthesia. The cannula was exteriorized at the nape of the neck. Blood samples (0.2-0.3 mL) were drawn from the jugular vein at intervals up to 24 hours after intravenous or oral administrations of the test compound. The samples were frozen until analysis. Bioavailability was assessed by calculating the quotient between the area under plasma concentration curve (AUC) following oral administration or intravenous administration,

Bioavailability in Dog

Adult Beagle dogs were used. Blood samples (0.2-0.5 mL) were drawn from the cephalic vein at intervals up to 24 hours after intravenous or oral administrations of the test compound. The samples were frozen until analysis. Bioavailability was assessed by calculating the quotient between the area under plasma concentration curve (AUC) following oral administration or intravenous administration.

Plasma Protein Binding

Plasma protein binding of the test compound (1 μM) was measured by the method of equilibrium dialysis using 96-well plate type equipment. Spectra-Por®, regenerated cellulose membranes (molecular weight cut-off 12,000-14,000, 22 mm×120 mm) were soaked for over night in distilled water, then for 20 minutes in 30% ethanol, and finally for 15 minutes in dialysis buffer (Dulbecco's phosphate buffered saline, pH7.4). Frozen plasma of human, Sprague-Dawley rats, and Beagle dogs were used. The dialysis equipment was assembled and added 150 μL of compound-fortified plasma to one side of each well and 150 μL of dialysis buffer to the other side of each well. After 4 hours incubation at 37° C. for 150 r.p.m, aliquots of plasma and buffer were sampled. The compound in plasma and buffer were extracted with 300 μL of acetonitrile containing internal standard compounds for analysis. The concentration of the compound was determined with LC/MS/MS analysis.

The fraction of the compound unbound was calculated by the following equation: fu=1−{([plasma]_(eq)−[buffer]_(eq))/([plasma]_(eq))} wherein [plasma]_(eq) and [buffer]_(eq) are the concentrations of the compound in plasma and buffer, respectively. Aqueous Solubility

Aqueous solubility in the mediums (a)-(c) was determined by following method:

Whatman mini-UniPrep chambers (Clifton, N.J., USA) containing more than 0.5 mg of compound and 0.5 mL of each medium were shaken overnight (over 8 hours) at room temperature. All samples were filtered through a 0.45 μm Polyvinylidene Difluoride (PVDF) membrane into the Whatman mini-UniPrep plunger before analysis. The filtrates were assayed by HPLC.

<medium> (a) Simulated gastric fluid with no enzyme (SGN) at pH 1.2: Dissolve 2.0 g of NaCl in 7.0 mL of 10 M HCl and sufficient water to make 1000 mL; (b) Phosphate buffer saline (PBS) at pH 6.5: Dissolve 6.35 g of KH₂PO₄, 2.84 g of Na₂HPO₄ and 5.50 g of NaCl in sufficient water to make 1000 mL, adjusting the pH to 6.5; (c) 3.94 mg of sodium taurocholate (NaTC) and 1.06 mg of 1-palmitoyl-2-oleyl-L-phosphatidylcholine (POPC) in 1 mL of PBS (pH 6.5). Estimation of Hepatic Clearance Using the Metabolic Stability in Human Hepatocytes

Tested compounds (1 μM) were incubated statically with hepatocytes from human at 37° C. in a 95% air/5% CO₂ with target cell density of 0.5×10⁶ cells/ml and a total volume of 50 μL. Incubation was stopped at each time point by the addition of ice-cold acetonitrile (ACN). Aliquots of samples were mixed with 10% ACN containing an internal standard for LC/MS/MS analysis. After samples were sonicated for 10 minutes, samples were centrifuged at 2,000 rpm for 15 minutes, and then the supernatant was transferred to the other plates for analysis. The compound concentrations in supernatant were measured by LC/MS/MS system.

The disappearance rates of tested compounds were obtained by plotting the common logarithm of the peak area ratio of compounds/internal standard versus time. The slope of the line of best fit through the points yielded the rate of metabolism (k_(e)). This value was scaled to take hepatocellularity, liver and body weight into account to give an intrinsic clearance value (CL_(int)) in ml/min/kg as illustrated in Equation 1. Hepatic clearance (CL_(h)) was predicted from this intrinsic clearance value using the parallel tube model as shown in Equation 2. The predicted clearance divided by the hepatic blood flow (Q_(h)) afforded the extraction ratio (E_(h)) (Equation 3). k _(e)×(g liver/kg body weight)×(ml incubation/number of cells in incubation)×(cells/g liver)  Equation 1: CL _(h) =Q _(h)×{1−exp(−CL _(int) /Q _(h))}  Equation 2: E _(h) =CL _(h) /Q _(h)  Equation 3: Wherein, “gliver weight/kg body weight” is 21, “Cells/g liver” is 1.2×10⁸, “ml incubation/number of cells in incubation” is 2.0×10⁻⁶, and Q_(h) is 20 ml/min/kg.

Supposing that hepatic metabolism is the main route of drug elimination, systemic exposure (AUC_(po)) after oral administration is calculated using Equation 4. AUC _(po)=Dose×(1−E _(h))/CL _(h)  Equation 4 Method for Assaying the Compounds Phototoxic Potential:

The phototoxic potential was measured in the strict accordance with method described in the OECD Guidelines for the Testing of Chemicals 432 (2002). Chlorpromazine (CPZ) and Sodium n-Dodecyl Sulfate (SDS) were used as positive and negative controls, respectively.

Balb/3T3, clone 31 cells (ATCC, CCL-163) were seeded into 96-wells plates (Nunc, 167008) at a density of 1×104 cells/well. Cells were incubated under a standard condition (37° C., a humidified atmosphere of 95% air and 5% CO2) within the culture medium-DMEM (GIBCO; cat#11885-084) for 24 hour. Following the incubation, the culture medium-DMEM was discarded and the cells were washed carefully with 150 μl of Earle's Balanced Salt Solution (EBSS; Sigma, Cat#E3024), then added 100 μl solution of the test compound in EBSS or solvent control (EBSS contained 1% dimethylsulphoxide or 1% ethanol). The plate was prepared in duplicate. All the plates were incubated under the standard condition for 60 min in the dark. One of the duplicated plates was used for determination of cytotoxicity (−Irr) and kept at room temperature in the dark for 50 min. For the determination of photocytotoxicity (+Irr), another one was exposed to the sun simulator (UVA irradiance: 1.7 mW/cm2; SOL500, Dr. Honle UV Technology, Germany) for 50 min (UVA dose=5 joules/cm2). Then the solutions were discarded from the two plates and immediately washed with 150 μl of EBSS with care. The cells were further incubated with 150 μl/well of DMED medium for 18-22 hr.

After the incubation, the culture medium was discarded, the cells were washed carefully with 150 μl of EBSS and then immediately incubated with 100 μl/well of a 50 μg/ml of neutral red (NR) (3-amino-7-dimethylamino-2-methylphenazine hydrochloride, Kanto Chemical Co., Inc., Japan) in DMEM without serum for 3 hour under the standard condition. After incorporation of neutral red into the cell lysosomes, the NR-DMED medium was discarded and the cells were washed carefully with 150 μl of EBSS. The exact 150 μl of ethanol/acetic acid/water (50:1:49) was added to each well of plate and the extraction was performed for 10 minutes by gently shaking at room temperature. Then optical density (OD) of the NR extract was measured at 540 nm using a spectrophotometer (Plate-reader, POLARstar OPTIMA; BMG Labtechnologies, Germany). The OD values were used to calculate the mean photo effect (MPE) value using OECD provided software “3T3 NRU Phototox”. (Version 2.0, Federal Institute for Risk Assessment, Germany). The results for the control (CPZ and SDS) were used for the quality assurance of the assay.

MPE value<0.1 was evaluated as “no-phototoxicity”; MPE value≧0.1 and ≦0.15 was evaluated as “probable phototoxicity” and MPE value≧0.15 was evaluated as “phototoxicity”.

EXAMPLES

The following examples are provided for the purpose of further illustration only and are not intended to be limitations on the disclosed invention. Unless stated on otherwise in the following examples, general experimental conditions are as follows: all operations were carried out at room or ambient temperature, that is, in the range of 18-25° C.; evaporation of solvent was carried out using a rotary evaporator under reduced pressure with a bath temperature of up to 60° C.; reactions were monitored by thin layer chromatography (TLC) and reaction times are given for illustration only; melting points (mp) given are uncorrected (polymorphism may result in different melting points): the structure and purity of all isolated compounds were assured by at least one of the following techniques: TLC (Merck silica gel 60 F₂₅₄ precoated TLC plates or Merck NH₂ gel (an amine coated silica gel) F_(254s) precoated TLC plates), mass spectrometry, nuclear magnetic resonance spectra (NMR), infrared absorption spectra (IR) or microanalysis. Yields are given for illustrative purposes only. Flash column chromatography was carried out using Biotage KP-SIL (40-63 μm), Biotage KP-NH (an amine coated silica gel) (40-75 μM), Fuji Silysia amino gel (30-50 μm) or Wako silica gel 300HG (40-60 μM). Microwave reactions were carried out using Personal Chemistry Emrys Optimizer or Biotage Initiator. Preparative TLC was carried out using Merck silica gel 60 F₂₅₄ precoated TLC plates (0.5 or 1-0 mm thickness). All Mass data was obtained in Low-resolution mass spectral data (ESI) using ZMD™ or ZQ™ (Waters) and mass spectrometer. NMR data were determined at 270 MHz (JEOL JNM-LA 270 spectrometer) or 300 MHz (JEOL JNM-LA300 spectrometer) using deuterated chloroform (99.8%) or dimethyl sulfoxide (99.9%) as solvent unless indicated otherwise, relative to tetramethylsilane (TMS) as internal standard in parts per million (ppm); conventional abbreviations used are: s=singlet, d=doublet, t=triplet, m=multiplet, dd=doublet of doublet, br.=broad, etc. IR spectra were measured by a Fourier transform infrared spectrophotometer (Shimazu FTIR-8300). Optical rotations were measured using a JASCO DOP-370 and P-1020 Digital Polarimeter (Japan Spectroscopic CO, Ltd.).

Example 1 4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide

STEP 1: N-{4-Bromo-2-nitro-6-[(phenylmethyl)oxy]phenyl}acetamide

To a solution of 4-bromo-2-nitro-6-[(phenylmethyl)oxy]aniline (33.0 g, 102 mmol, WO 2004054984) and acetic anhydride (14.5 mL, 153 mmol) in acetic acid (90 mL) was added concentrated sulfuric acid (2 drops) at 70° C. The mixture was stirred at 70° C. for 20 minutes. After cooling to room temperature, water (800 mL) was added, and the formed precipitate was collected by filtration, and washed with diisopropyl ether to give the title compound as a brown solid (30.9 g, 83%).

¹H NMR (CDCl₃, 270 MHz) δ: 7.69 (d, J=2.0 Hz, 1H), 7.56 (br. s, 1H), 7.47-7.38 (m, 5H), 7.34 (d, J=2.0 Hz, 1H), 5.14 (s, 2H), 2.16 (s, 3H) ppm. MS (ESI) m/z: 365 (M+H)⁺.

STEP 2: N-{4-Cyano-2-nitro-6-[(phenylmethyl)oxy]phenyl}acetamide

A mixture of N-{4-bromo-2-nitro-6-[(phenylmethyl)oxy]phenyl}acetamide (6.5 g, 17.8 mmol, STEP 1), zinc cyanide (4.18 g, 35.6 mmol), and tetrakis(triphenylphosphine)palladium (2.06 g, 1.78 mmol) in N,N-dimethylformamide (100 mL) was heated to 170° C. for 20 minutes in the microwave synthesizer (Biotage, Emrys Optimizer). After cooling to room temperature, the suspension was filtered, and washed with ethyl acetate. The organic layers were combined, washed with water, dried over magnesium sulfate, and concentrated in vacuum. The residual solid was purified by column chromatography on silica gel eluting with hexane/ethyl acetate (3:1) to afford the title compound as a white solid (5.5 g, 99%).

¹H NMR (CDCl₃, 300 MHz) δ: 7.92 (s, 1H), 7.83 (s, 1H), 7.53-7.33 (m, 5H), 7.39 (s, 1H), 5.21 (s, 2H), 2.21 (s, 3H) ppm. MS (ESI) m/z: 312 (M+H)⁺, 310 (M−H)⁻.

STEP 3: 2-Methyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carbonitrile

A mixture of N-{4-cyano-2-nitro-6-[(phenylmethyl)oxy]phenyl}acetamide (5.5 g, 17.7 mmol, STEP 2) and iron powder (2.96 g, 53.0 mmol) in acetic acid (90 mL) was refluxed with stirring for 2 hours. After cooling to room temperature, the mixture was filtered through a pad of Celite, and the filtrate was concentrated in vacuum. The residue was poured into water, and the aqueous layer was extracted with ethyl acetate/methanol (20:1). The organic layers were combined, washed with brine, dried over magnesium sulfate, and concentrated in vacuum to afford the title compound as a brown solid (3.82 g, 82%).

¹H NMR (DMSO-d₆, 300 MHz) δ: 7.64 (s, 1H), 7.64-7.27 (m, 6H), 7.19 (s, 1H), 5.34 (s, 2H), 2.50 (s, 3H) ppm. MS (ESI) m/z: 264 (M+H)⁺, 262 (M−H)⁻.

STEP 4: 2-Methyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carboxylic Acid

A solution of 2-methyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carbonitrile (3.82 g, 14.5 mmol, STEP 3) and potassium hydroxide (85%, 10.2 g, 15.4 mmol) in ethylene glycol (50 mL) was heated to 170° C. for 20 minutes in the microwave synthesizer (Biotage, Emrys Optimizer). After cooling to room temperature, the mixture was acidified with 2M hydrochloric acid aqueous solution (pH=3). The precipitated solid was collected by filtration to afford the title compound as a white solid (3.83 g, 93%).

¹H NMR (DMSO-d₆, 270 MHz) δ: 12.68 (br. s, 1H), 7.74 (s, 1H), 7.64-7.01 (m, 7H), 5.33 (s, 2H), 2.50 (s, 3H) ppm. MS (ESI) m/z: 283 (M+H)⁺, 281 (M−H)⁻.

STEP 5: N,N,2-Trimethyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carboxamide

A mixture of 2-methyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carboxylic acid (5.0 g, 17.7 mmol, STEP 4), dimethylamine hydrochloride (4.33 g, 53.1 mmol), 2-[1H-benzotriazole-1-yl]-1,1,3,3-tetramethyluronium hexafluorophosphate (10.1 g, 26.6 mmol), and triethylamine (10.7 g, 106 mmol) in N,N-dimethylformamide (80 mL) was stirred at room temperature for 1 hour. The mixture was diluted with ethyl acetate/methanol (20:1), and washed with saturated ammonium chloride aqueous solution. The organic layer was dried over magnesium sulfate, and concentrated in vacuum. The residue was purified by column chromatography on silica gel (gradient elution from ethyl acetate only to ethyl acetate methanol 5:1) to afford the title compound as a white solid (4.90 g, 89%).

¹H NMR (CDCl₃, 270 MHz) δ: 7.47-7.23 (m, 5H), 7.20 (s, 1H), 6.75 (s, 1H), 5.22 (s, 2H), 2.95 (br. s, 6H), 2.54 (s, 3H) ppm (—NH was not observed). MS (ESI) m/z: 310 (M+H)⁺, 308 (M−H)⁻.

STEP 6: N,N,2-Trimethyl-1-[(4-methylphenyl)sulfonyl]-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carboxamide

To a suspension of N,N,2-trimethyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carboxamide (928 mg, 3.0 mmol, STEP 5) in N,N-dimethylformamide (20 mL) was added sodium hydride (60% in mineral oil, 180 mg, 4.50 mmol) at 0° C. After stirring at room temperature for 30 minutes, the reaction mixture was cooled to 0° C. To the mixture was added 4-methylbenzenesulfonyl chloride (572 mg, 3.00 mmol) at 0° C., and the reaction mixture was stirred at room temperature for 2 hours. The mixture was poured into water, and the aqueous layer was extracted with ethyl acetate. The organic layers were combined, washed with water, dried over magnesium sulfate and concentrated in vacuum. The residue was purified by column chromatography on silica gel (gradient elution from dichloromethane only to ethyl acetate only) to afford the title compound as a white solid (1.00 g, 72%).

¹H NMR (CDCl₃,270 MHz) δ: 7.80 (d, J=8.1 Hz, 2H), 7.70 (s, 1H), 7.45 (d, J=831 Hz, 2H), 7.40-7.22 (m, 5H), 6.86 (s, 1H), 5.32 (s, 2H), 3.11 (br. s, 3H), 2.89 (br s, 3H), 2.81 (s, 3H), 2.40 (s, 3H) ppm. MS (ESI) m/z: 464 (M+H)⁺.

STEP 7: 4-Hydroxy-N N,2-trimethyl-1-[(4-methylphenyl)sulfonyl]-1H-benzimidazole-6-carboxamide

A mixture of N,N,2-trimethyl-1-[(4-methylphenyl)sulfonyl]-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carboxamide (350 mg, 0.756 mmol, STEP 6) and 20% palladium hydroxide (1.20 g) in acetic acid (20 mL) was stirred under hydrogen gas (4 atmospheres) for 4 hours. The resulted mixture was filtered through a pad of Celite, and the filtrate was concentrated in vacuum. The residue was purified by column chromatography on silica gel (gradient elution from ethyl acetate only to ethyl acetate:methanol 5:1) to afford the title compound as a white solid (131 mg, 36%).

¹H NMR (CDCl₃, 270 MHz) δ: 7.82 (d, J=8.1 Hz, 2H), 7.63 (s, 1H), 7.31 (d, J=8.1 Hz, 2H), 6.92 (s, 1H), 3.14 (br. s, 3H), 3.01 (br. s, 3H), 2.79 (s, 3H), 2.40 (s, 3H) ppm (—OH was not observed). MS (ESI) m/z: 374 (M+H)⁺, 372 (M−H)⁻.

STEP 8: 4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1-[(4-methylphenyl)sulfonyl]-1H-benzimidazole-6-carboxamide STEP 8-1: 5,7-Difluoro-3,4-dihydro-2H-chromen-4-ol

To a solution of 5,7-difluoro-2,3-dihydro-4H-chromen-4-one (14.2 g, 77.0 mmol, US 20050038032) in methanol (200 mL) was added sodium borohydride (3.50 g, 92.5 mmol) at 0° C. The reaction mixture was stirred at the same temperature for 1 hour, and evaporated to remove methanol. The residue was quenched with water, and extracted with ethyl acetate. The extract was washed with brine, dried over magnesium sulfate, and concentrated in vacuum. The residue was purified by column chromatography on silica gel (hexane:ethyl acetate=3:1 as an eluent) to afford the title compound as a pale gray solid (9.64 g, 67%).

¹H NMR (CDCl₃, 270 MHz) δ: 6.47-6.36 (m, 2H), 5.05-4.97 (m, 1H), 4.36-4.20 (m, 2H), 2.16-1.92 (m, 3H) ppm.

STEP 8-2: 4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1-[(4-methylphenyl)sulfo nyl]-1H-benzimidazole-6-carboxamide

To a stirred mixture of 4-hydroxy-N,N,2-trimethyl-1-[(4-methylphenyl)sulfonyl]-1H-benzimidazole-6-carboxamide (110 mg, 0.294 mmol, STEP 7), 5,7-difluoro-3,4-dihydro-2H-chromen-4-ol (164 mg, 0.884 mmol, STEP 8-1) and triphenylphosphine (232 mg, 0.884 mmol) in toluene (5 mL) was added diisopropyl azodicarboxylate (DIAD) (179 mg, 0.884 mmol) at room temperature. The reaction mixture was stirred at room temperature for 6 hours and concentrated in vacuum. The residue was purified by column chromatography on silica gel (ethyl acetate:hexane gradient elution from 1:20 to 10:1) to afford a mixture of the title compound and triphenylphosphine oxide (280 mg, crude) as white solids, which was used in the next step without further purification.

¹H NMR (CDCl₃, 270 MHz) δ: 7.81 (d, J=8.1 Hz, 2H), 7.51 (s, 1H), 7.31 (d, J=8.1 Hz, 2H), 7.07 (s, 1H), 6.54-6.22 (m, 2H), 5.93 (br. s, 1H), 4.40 (t, J=10.8 Hz, 1H), 4.27 (t, J=10.8 Hz, 1H), 3.15 (br. s, 3H), 3.03 (br. s, 3H), 2.79 (s, 3H), 2.39 (s, 3H), 2.40-2.21 (m, 1H), 2.19-1.73 (m, 1H) ppm. MS (ESI) m/z: 542 (M+H)⁺, 540 (M−H)⁻.

STEP 9: 4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide

To a solution of 4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1-[(4-methylphenyl)-sulfonyl]-1H-benzi midazole-6-carboxamide (280 mg, crude, STEP 8) in tetrahydrofuran (8 mL) and methanol (4 mL) was added sodium hydroxide (165 mg, 4.1 mmol) at room temperature. After stirring at room temperature for 1 hour, the mixture was quenched with saturated sodium dihydrogenphosphate aqueous solution, and extracted with ethyl acetate. The organic layers were combined, dried over magnesium sulfate and concentrated in vacuum. The residue was purified by column chromatography on silica gel (gradient elution from dichloromethane only to ethyl acetate:methanol 10:1) to afford the title compound as a white solid (74 mg, 65% for 2 steps).

¹H NMR (CDCl₃, 270 MHz) δ: 7.27 (s, 1H), 6.95 (s, 1H), 6.51-6.33 (m, 2H), 5.87-5.69 (m, 1H), 4.41-4.25 (m, 2H), 3.10 (br. s, 6H), 2.56 (s, 3H), 2.44-2.34 (m, 1H), 2.14-1.98 (m, 1H) ppm (—NH was not observed). MS (ESI) m/z: 388 (M+H)⁺, 386 (M−H)⁻.

Example 2 (−)-4-[((4S)-5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1 fl-benzimidazole-6-carb oxamide and Example 3 (−)-4-[((4R)-5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benximidazole-6-carboxamide

The fraction-1 (582 mg) and fraction-2 (562 mg) were prepared from racemic 4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N, 1,2-trimethyl-1H-benzimidazole-6-carboxamide (1.63 g, STEP 9 in Example 1) by HPLC as follows.

Isolation Condition

Column: CHIRALCEL OJ-H (20 mm×250 mm, DAICEL)

Mobile phase: n-Hexane/Ethanol/Diethylamine (95/5/0.1)

Flow fate: 18.9 mL/min

(−)-4-[((4S)-5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide (fraction-1)

¹H NMR: spectrum data were identical with those of the racemate

optical rotation: [α]_(D) ²³=−101.1° (c=1.00, Methanol)

retention time: 14 min

(+)-4-[((4R)-5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide (fraction-2)

¹H NMR: spectrum data were identical with those of the racemate

optical rotation: [α]_(D) ²³=+104.2° (c=1.00, Methanol)

retention time: 18 min

The following is the alternative method for synthesizing (−)-4-[((4S)-5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide.

STEP 1: 6-Bromo-2-methyl-4-[(phenylmethyl)oxy]-1H-benzimidazole

A mixture of N-{4-bromo-2-nitro-6-[(phenylmethyl)oxy]phenyl}acetamide (120 g, 329 mmol, STEP 1 in Example 1) and iron powder (55.1 g, 986 mmol) in acetic acid (500 mL) was refluxed with stirring for 6 hours. After cooling to room temperature, the mixture was filtered through a pad of Celite, and the filtrate was concentrated in vacuum. The residue was diluted with ethyl acetate (1.5 L). The resulted precipitates were filtered through a pad of Celite, and washed with ethyl acetate (500 mL). The filterate was concentrated in vacuum, and the residue was diluted with ethyl acetate (200 mL). The brine (800 mL) was added to the organic mixture, the resulted white precipitates were collected by filtration, and washed with water (200 mL) and diethyl ether (200 mL). The white solid was dissolved with dichloromethane/methanol (10:1, 1.0 L), dried over magnesium sulfate, and concentrated. The solid was triturated with diethyl ether (300 mL), collected by filtration, and dried in vacuum to afford the title compound as a white solid (54.7 g, 53%).

¹H NMR (DMSO-d₆, 270 MHz) δ: 7.63-7.28 (m, 7H), 5.38 (s, 2H), 2.69 (s, 3H) ppm. (NH was not observed.) MS (ESI) m/z: 317 (M+H)⁺, 315 (M−H)⁻.

STEP 2: 6-Bromo-2-methyl-1-[(4-methylphenyl)sulfonyl]-4-[(Phenylmethyl)oxy]-1H-benzimidazole

To a suspension of 6-bromo-2-methyl-4-[(phenylmethyl)oxy]-1H-benzimidazole (79.2 g, 250 mmol, STEP 1) in N,N-dimethylformamide (500 mL) was added sodium hydride (60% in mineral oil, 12.0 g, 300 mmol) at 0° C. After stirring at room temperature for 20 minutes, the reaction mixture was cooled to 0° C. To the mixture was added 4-methylbenzenesulfonyl chloride (47.6 g, 250 mmol) at 0° C., and the reaction mixture was stirred at room temperature for 30 minutes. The mixture was quenched with water (800 mL), and the white precipitates were collected by filtration, washed with diisopropyl ether (500 mL), and dried in vacuum at 70° C. for 7 hours to afford the title compound as a white solid (116 g, 98%).

¹H NMR (DMSO-d₆, 270 MHz) δ: 7.98 (d, J=8.1 Hz, 2H), 7.64 (d, J=1.9 Hz, 1H), 7.53-7.34 (m, 7H), 7.22 (d, J=1.9 Hz, 1H), 5.28 (s, 2H), 2.74 (s, 3H), 2.38 (s, 3H) ppm. MS (ESI) m/z: 471 (M+H)⁺, 469 (M−H)⁻.

STEP 3: N,N,2-Trimethyl-1-[(4-methylphenyl)sulfonyl]-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carboxamide

A mixture of 6-bromo-2-methyl-1-[(4-methylphenyl)sulfonyl]-4-[(phenylmethyl)oxy]-1H-benzimidazole (53.0 g, 112 mmol, STEP 2) and tetrakis(triphenylphosphine)palladium(0) (25.9 g, 22.4 mmol) in 2M dimethylamine tetrahydrofuran solution (580 mL) was stirred at 65° C. under carbon mono-oxide gas (1 atmosphere) for 32 hours. The mixture was cooled to room temperature, and diluted with ethyl acetate (600 mL). The organic mixture was washed with saturated ammonium chloride aqueous solution (800 mL) and brine (500 mL), dried over magnesium sulfate and concentrated in vacuum. The residue was purified by column chromatography on silica gel (hexane:ethyl acetate gradient elution from 1:2 to 1:3) to afford the title compound as a white solid (21.8 g, 42%).

¹H NMR: spectrum data were identical with STEP 6 in Example 1.

STEP 4: 4-Hydroxy-N,N,2-trimethyl-1-[(4-methylphenyl)sulfonyl]-1H-benzimidazole-6-carboxamide

A mixture of N,N,2-trimethyl-1-[(4-methylphenyl)sulfonyl]-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carboxamide (29.0 g, 62.6 mmol, STEP 3) and 10% palladium on carbon (6.0 g) in tetrahydrofuran (200 mL) was stirred under hydrogen gas (1 atmosphere) at room temperature for 24 hours. Another 4.0 g of 10% palladium on carbon was added, and the mixture was stirred under hydrogen gas (1 atmosphere) at room temperature for additional 6 hours. The resulted mixture was filtered through a pad of Celite, and the filtrate was concentrated in vacuum to afford the title compound as a white solid (23.0 g, 98%).

¹H NMR: spectrum data were identical with STEP 7 in Example 1.

STEP 5: Methyl 3-(3,5-difluorophenoxy)acrylate

A solution of 3,5-difluorophenol (35.5 g, 273 mmol) and methyl propiolate (25.0 mL, 300 mmol) in acetonitrile (109 mL) was added to a solution of tetrabutylammonium fluoride in tetrahydrofuran (1.0 M commercial solution, 109 mL, 109 mmol) at room temperature over a period of 2 hours. After complete addition of the solution, the mixture was stirred for 1 hour. The reaction mixture was diluted with toluene (350 mL) and the organic mixture was washed twice with water (250 mL×2), dried over magnesium sulfate, and concentrated in vacuum. The residue was purified by column chromatography on amino gel (hexane:ethyl acetate=3:2 as an eluent) to afford the title compound as a yellow solid (60.0 g, quant, 1:1 mixture of cis- and trans-isomers).

¹H NMR (CDCl₃, 270 MHz,) δ: 7.72 (d, J=10.8 Hz, 0.5H), 6.83 (d, J=5.4 Hz, 0.5H), 6.74-6.49 (m, 3H), 5.68 (d, J=10.8 Hz, 0.5H), 5.28 (d, J=5.4 Hz, 0.5H), 3.76 (s, 3H) ppm.

STEP 6: Methyl 3-(3,5-difluorophenoxy)propanoate

A mixture of methyl 3-(3,5-difluorophenoxy)acrylate (60.0 g, 280 mmol, STEP 5), and 10% palladium on carbon (1.0 g) in methanol (300 mL) was stirred under hydrogen gas (1 atmosphere) at room temperature for 18 hours. The reaction mixture was filtered through a pad of Celite, and washed with toluene (100 mL). The filtrate was concentrated in vacuum to afford the title compound (61.0 g, quant) as a colorless oil, which was used in the next step without further purification.

¹H NMR (CDCl₃, 270 MHz) δ: 6.56-6.21 (m, 3H), 4.21 (t, J=5.4 Hz, 2H), 3.74 (s, 3H), 2.80 (t, J=5.4 Hz, 2H) ppm.

STEP 7: 5,7-Difluoro-2,3-dihydro-4H-chromen-4-one

A mixture of methyl 3-(3,5-difluorophenoxy)propanoate (11.6 g, 53.7 mmol, STEP 6) and trifluoromethanesulfonic acid (23.2 mL, 2.0 mL/g of substrate) was stirred at 80° C. for 2 hours. After cooling to room temperature, the reaction mixture was diluted with water (120 mL), and extracted with toluene (120 mL). The organic layer was washed successively with aqueous solution of potassium carbonate (50 mL), water (50 mL), and dried over magnesium sulfate. The organic mixture was concentrated in vacuum to afford the title compound (8.75 g, 88%) as a white solid, which was used in the next step without further purification.

¹H NMR (CDCl₃, 270 MHz) δ: 6.51-6.40 (m, 2H), 4.55-4.50 (m, 2H), 2.86-2.75 (m, 2H) ppm.

STEP 8: (+)-5,7-Difluoro-3,4-dihydro-2H-chromen-4-ol

To a mixture of 1 M (S)-tetrahydro-1-methyl-3,3-diphenyl-1H,3H-pyrrolo[1,2-c][1,3,2]oxazaborole toluene solution (5.43 mL, 5.43 mmol) and tetrahydrofuran (40 mL) was added 2M borane-methyl sulfide complex tetrahydrofuran solution (29.8 mL, 59.7 mmol) at 0° C. and the mixture was stirred for 20 minutes. To the mixture was added a solution of 5,7-difluoro-2,3-dihydro-4H-chromen-4-one (10.0 g, 54.3 mmol, STEP 7) in tetrahydrofuran (70 mL) at 0° C. over a period of 1 hour, and the mixture was stirred at the same temperature for 1 hour. The reaction mixture was quenched with methanol (50 mL) and stirred for 30 minutes at room temperature. The mixture was concentrated in vacuum and the residue was purified by column chromatography on silica gel (hexane:ethyl acetate=4:1 as an eluent) to afford crude white solids (8.85 g, 86% ee). The solids were recrystallized from hexane (300 mL) to give the title compound as a colorless needle crystal (5.90 g, 58%, >99% ee).

¹H NMR: spectrum data were identical with those of the racemate (STEP 8-1 in Example 1).

optical rotation: [α]_(D) ²⁴=+143.6° (c=1.00, Methanol).

STEP 9: (−)-4-[((4S)-5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1-[(4-methylphenyl) sulfonyl]-1H-benzimidazole-6-carboxamide

To a stirred mixture of 4-hydroxy-N,N,2-trimethyl-1-[(4-methylphenyl)sulfonyl]-1H-benzimidazole-6-carboxamide (21.2 g, 56.8 mmol, STEP 4), (+)-5,7-difluoro-3,4-dihydro-2H-chromen-4-ol (15.86 g, 85.1 mmol, STEP 8) and tributylphosphine (22.9 g, 113 mmol) in toluene (840 mL) was added 1,1′-(azodicarbonyl)dipiperidine (ADDP) (19.3 g, 76.5 mmol) at room temperature. After stirring at room temperature for 2 hours, the reaction mixture was filtered through a pad of Celite and washed with ethyl acetate (300 mL). The filtrate was concentrated in vacuum. The residue was purified by column chromatography on silica get (ethyl acetate:hexane gradient elution from 1:20 to 20:1) to afford crude solids (27.0 g). The solids were recrystallized from 2-propanol (130 mL) to give the title compound as a colorless crystal (23.2 g, 75%, >99% ee)

¹H NMR: spectrum data were identical with those of the racemate (STEP 8-2 in Example 1).

optical rotation: [α]_(D) ²⁴=80.4° (c=0.50, Methanol).

STEP 10: (−)-4-[((4S)-5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide

To a solution of (−)-4-[((4S)-5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1-[(4-methylphenyl)-sulfonyl]-1H-benzimidazole-6-carboxamide (24.2 g, 44.7 mmol, STEP 9) in tetrahydrofuran (65 mL) and 2-propanol (220 mL) was added 2M sodium hydroxide aqueous solution (220 mL, 440 mmol) at room temperature. After stirring at room temperature for 4 hours, the mixture was diluted with ethyl acetate (1.20 L) and washed with saturated ammonium chloride aqueous solution (500 mL). The organic solution was dried over magnesium sulfate and concentrated in vacuum. The residue was purified by column chromatography on amino gel (ethyl acetate:methanol gradient elution from 50:1 to 20:1) to afford the title compound as a white solid (15.2 g, 87%, >99% ee).

¹H NMR: spectrum data were identical with those of the racemate (STEP 9 in Example 1).

Optical rotation and retention time were identical with the above.

Example 4 4-[(57 Difluoro-3,4-dihydro-2H-chromen-4-yl oxy]-2-methyl-6-pyrrolidin-1-ylcarbonyl)-1H-benzimidazole

STEP 1: Methyl 2-methyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carboxylate

A mixture of 2-methyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carboxylic acid (10.0 g, 35.4 mmol, STEP 4 in Example 1), and thionyl chloride (5.2 mL, 7.1 mmol) in methanol (300 mL) was stirred at 80° C. for 3 hours. The mixture was diluted with ethyl acetate, and washed with saturated ammonium chloride aqueous solution. The organic layer was dried over magnesium sulfate, and concentrated in vacuum. The residue was diluted with methanol, filtered to remove the precipitate, and the filtrate was concentrated in vacuum. The resulted solid was washed with dichloromethane to give the title compound as a brown solid (29.8 g, crude), which was used in the next step without further purification. MS (ESI) m/z: 297 (M+H)⁺, 295 (M−H)⁻.

STEP 2: 1-(1,1-Dimethylethyl) 6-methyl 2-methyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-1,6-dicarboxylate

A mixture of methyl 2-methyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carboxylate (29.8 g, crude, STEP 1), di-tert-butyl-dicarbonate (69 g, 315 mmol), 4-dimethylaminopyridine (366 mg, 3.0 mmol) and triethylamine (100 mL, 717 mmol) in N,N-dimethylformamide (100 mL) was stirred at room temperature for 2 hours. The mixture was diluted with ethyl acetate, and washed with saturated ammonium chloride aqueous solution. The organic layer was dried over magnesium sulfate, and concentrated in vacuum. The residue was purified by column chromatography on silica gel (ethyl acetate:hexane gradient elution from 1:20 to 3:2) to afford the title compound (12.1 g, crude) as a white solid, which was used in the next step without further purification.

¹H NMR (CDCl₃, 270 MHz) δ: 8.29 (s, 1H), 7.54 (s, 1H), 7.60-7.50 (m, 2H), 7.40-7.31 (m 3H), 5.37 (s, 2H), 3.92 (s, 3H), 2.86 (s, 3H), 1.73 (s, 9H) ppm. MS (ESI) m/z: 397 (M+H)⁺.

STEP 3: 1-(1,1-Dimethylethyl) 6-methyl 4-hydroxy-2-methyl-1H-benzimidazole-1,6-dicarboxylate

A mixture of 1-(1,1-dimethylethyl) 6-methyl 2-methyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-1,6-dicarboxylate (12.1 g, crude, STEP 2) and 20% palladium hydroxide (6.0 g) in tetrahydrofuran (250 mL) was stirred under hydrogen gas for 2 hours. The resulted mixture was filtered through a pad of Celite, and the filtrate was concentrated in vacuum. The residue was washed with hexane/diethyl ether (10:1) to give the title compound as a white solid (3.02 g, 28% for 3 steps).

¹H NMR (CDCl₃, 270 MHz) δ: 10.38 (br. s, 1H), 8.21 (s, 1H), 7.62 (s, 1H), 3.94 (s, 3H), 2.87 (s, 3H), 1.73 (s, 9H) ppm. MS (ESI) m/z: 307 (M+H)⁺, 305 (M−H)⁻.

STEP 4: 4-4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-1H-benzimidazole-6-carboxylic Acid

To a stirred mixture of 1-(1,1-dimethylethyl) 6-methyl 4-hydroxy-2-methyl-1H-benzimidazole-1,6-dicarboxylate (1.50 g, 4.90 mmol, STEP 3), 5,7-difluoro-3,4-dihydro-2H-chromen-4-ol (1.82 g, 9.79 mmol, STEP8-1 in Example 1) and triphenylphosphine (2.57 g, 9.79 mmol) in toluene (50 mL) was added diisopropyl azodicarboxylate (DIAD) (1.98 g, 4.90 mmol) at room temperature. The reaction mixture was stirred at room temperature for 2 hours and concentrated in vacuum. The residue was dissolved in methanol (20 mL) and tetrahydrofuran (5 mL), and 4M lithium hydroxide aqueous solution (20 mL, 80 mmol) was added to the mixture at room temperature. After stirring for 4 hours at 80° C., the reaction mixture was concentrated in vacuum. The residue was dissolved with water, washed with ethyl acetate, and acidified (pH=6) with 2M hydrochloric acid aqueous solution. The precipitated solid was filtrated, and dried in vacuum to afford the title compound as a white solid (1.67 g, crude), which was used in the next step without further purification.

¹H NMR (DMSO-d₆, 270 MHz) δ: 7.76 (s, 1H), 7.51 (s, 1H), 6.79 (t, J=10.8 Hz, 1H), 6.66 (t, J=10.8 Hz, 1H), 5.99 (br. s, 1H), 4.39-4.17 (m, 2H), 2.46 (s, 3H), 2.28-2.05 (m, 2H) ppm (—COOH and —NH were not observed). MS (ESI) m/z: 361 (M+H)⁺, 359 (M−H)⁻.

STEP 5: 4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-6-(pyrrolidin-1-ylcarbonyl)-1H-benzimidazole

The title compound was prepared as a white solid (70 mg, 56% yield for 3 steps) from 4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-1H-benzimidazole-6-carboxylic acid (100 mg, crude, STEP 4) and pyrrolidine (59 mg, 0.832 mmol) by the same manner in STEP 5 of Example 1.

¹H NMR (CDCl₃, 270 MHz) δ: 7.33 (s, 1H), 7.03 (s, 1H), 6.47-6.07 (m, 2H), 5.90-5.66 (m, 1H), 4.40-4.18 (m, 2H), 3.73-3.40 (m, 4H), 2.48 (s, 3H), 2.37-2.22 (m, 1H), 2.11-1.78 (m, 5H) ppm (—NH was not observed). MS (ESI) m/z: 414 (M+H)⁺, 412 (M−H)⁻.

Example 5 (+)-4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-6-(pyrrolidin-1-ylcarbonyl)-1H-benzimidazole and Example 6 (−)-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-6-pyrrolidin-1-ylcarbonyl)-1H-benzi midazole

The fraction-1 (152 mg) and fraction-2 (146 mg) were prepared from racemic 4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-6-(pyrrolidin-1-ylcarbonyl)-1H-benzimidazole (0.35 g, STEP 5 in Example 4) by HPLC as follows.

Isolation Condition

Column: CHIRALPAK AD-H (20 mm×250 mm, DAICEL)

Mobile phase: n-Hexane/iso-Propanol/Diethylamine (85/15/0.1)

Flow rate: 20 mL/min

(+)-4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-6-(pyrrolidin-1-ylcarbonyl)-1H-benzimidazole (fraction-1)

¹H NMR: spectrum data were identical with those of the racemate

optical rotation: [α]_(D) ²³=+105.0° (c=0.50, Methanol)

retention time: 12 min

(−)-4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-6-(pyrrolidin-1-ylcarbonyl)-1H-benzimidazole (fraction-2)

¹H NMR: spectrum data were identical with those of the racemate

optical rotation: [α]_(D) ²³-106.5° (c=0.50, Methanol)

retention time: 14 min

Example 7 4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N-(2-hydroxyethyl)-N,2-dimethyl-1H-benzimidazole-6-carboxamide

The title compound was prepared as a white solid (50 mg, 40% yield for 3 steps) from 4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-1H-benzimidazole-6-carboxylic acid (100 mg, crude, STEP 4 in Example 4) and 2-(methylamino)ethanol (63 mg, 0.83 mmol) by the same manner in STEP 5 of Example 1.

¹H NMR (CDCl₃ 270 MHz) δ: 6.91 (br. s, 2H), 6.49-6.23 (m, 2H) 5.88-5.65 (m, 1H), 4.37-4.11 (m, 2H), 3.99-3.60 (m, 3H), 3.07 (s, 3H), 2.41 (s, 3H), 2.36-2.17 (m, 1H), 2.08-1.89 (m, 2H) ppm (—OH and —NH were not observed). MS (ESI) m/z: 418 (M+H)⁺, 416 (M−H)⁻.

Example 8 4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N-[2-(dimethylamino)ethyl]-N,2-dimethyl-1H-benzimidazole-6-carboxamide

The title compound was prepared as a white solid (10 mg, 13% yield for 3 steps) from 4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-1H-benzimidazole-6-carboxylic acid (100 mg, crude, STEP 4 in Example 4) and N,N,N′-trimethyl-1,2-ethanediamine (45 mg, 0.44 mmol) by the same manner in STEP 5 of Example 1.

¹H NMR (CDCl₃ 270 MHz) δ: 7.27 (s, 1H), 6.94 (s, 1H) 6.50-6.31 (m, 2H), 5.76 (br. s, 1H), 4.44-4.24 (m, 2H), 3.76-3.32 (m, 2H), 3.09 (s, 5H), 2.56 (s, 3H), 2.61-1.94 (m, 10H) ppm (—NH was not observed). MS (ESI) m/z: 445 (M+H)⁺, 443 (M−H)⁻.

Example 9 4-[5-Fluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide

STEP 1: 1,1-Dimethylethyl 6-[(dimethylamino)carbonyl]-2-methyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-1-carboxylate

The title compound was prepared as a white solid in 67% yield (5.68 g) from N,N,2-trimethyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-6-carboxamide (6,4 g, 20.7 mmol, STEP 5 in Example 1) and di-tert-butyl-dicarbonate (6.77 g, 31.0 mmol) by the same manner in STEP 2 of Example 4.

¹H NMR (CDCl₃ 270 MHz) δ: 7.64 (s, 1H), 7.47 (d, J=8.1 Hz, 2H), 7.38-7.28 (m, 3H), 6.83 (s, 1H), 5.38 (s, 2H), 2.97 (br. s, 6H), 2.83 (s, 3H), 1.69 (s, 9H) ppm; MS (ESI) m/z: 410 (M+H)⁺.

STEP 2: 1,1-Dimethylethyl 6-[(dimethylamino)carbonyl]-4-hydroxy-2-methyl-1H-benzimidazole-1-carboxylate

The title compound was prepared as a white solid in 92% yield (4.10 g) from 1,1-dimethylethyl 6-[(dimethylamino)carbonyl]-2-methyl-4-[(phenylmethyl)oxy]-1H-benzimidazole-1-carboxylate (5.68 g, 13.9 mmol, STEP 1) and 20% palladium hydroxide (2.4 g) by the same manner in STEP 3 of Example 4.

¹H NMR (CDCl₃ 270 MHz) δ: 10.39 (s, 1H), 7.56 (s, 1H), 6.97 (s, 1H), 3.13 (br. s, 3H), 3.04 (br. s, 3H), 2.82 (s, 3H), 1.69 (s, 9H) ppm. MS (ESI) m/z: 320 (M+H)⁺, 318 (M−H)⁻.

STEP 3: 4-[(5-Fluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide STEP 3-1: 5-Fluoro-3,4-dihydro-2H-chromen-4-ol

The title compound was prepared as a black oil in quantitative yield (0.9 g) from 5-fluoro-2,3-dihydro-4H-chromen-4-one (0.9 g, 5 mmol, GB 2355264) by the same manner in STEP 8-1 of Example 1.

¹H NMR (CDCl₃, 300 MHz) δ: 7.25-7.11 (m, 1H), 6.75-6.60 (m, 2H), 5.13-5.02 (m, 1H), 4.40-4.18 (m, 2H), 2.25-1.95 (m, 3H) ppm.

STEP 3-2: 4-[(5-Fluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1-H-benzimidazole-6-carboxamide

To a stirred mixture of 1,1-dimethylethl 6-[(dimethylamino)carbonyl]-4-hydroxy-2-methyl-1H-benzimidazole-1-carboxylate (1.00 g, 3.13 mmol, STEP 2), 5-fluoro-3,4-dihydro-2H-chromen-4-ol (948 mg, 5.64 mmol, STEP 3-1) and triphenylphosphine (2.57 g, 9.79 mmol) in toluene (50 mL) was added diisopropyl azodicarboxylate (DIAD) (1.98 g, 4.90 mmol) at room temperature. The reaction mixture was stirred at room temperature for 2 hours and concentrated in vacuum. The residue was dissolved in tetrahydrofuran (30 mL) and methanol (15 mL), and sodium hydroxide (750 mg, 18.8 mmol) was added to the mixture at room temperature. After stirring at room temperature for 1 hour, the mixture was quenched with saturated sodium dihydrogenphosphate aqueous solution, and extracted with ethyl acetate. The organic layers were combined, dried over magnesium sulfate and concentrated in vacuum. The residue was purified by column chromatography on silica gel (dichloromethane only then ethyl acetate methanol 10:1 as an eluent) to afford the title compound as a white solid (510 mg, 50%).

¹H NMR (CDCl₃, 270 MHz) δ; 7.20-7.11 (m, 1H), 7.13 (s, 1H), 6.90 (s, 1H), 6.64 (d, J=8.1 Hz, 1H), 6.52 (d, J=8.1 Hz, 1H), 5.76 (br. s, 1H), 4.28-4.07 (m, 2H), 3.04 (br. s, 6H), 2.38 (s, 3H), 2.29-2.18 (m, 1H), 2.04-1.90 (m, 1H) ppm (—NH was not observed). MS (ESI) m/z: 370 (M+H)⁺, 368 (M−H)⁻.

Example 10 (−)-4-[(5-Fluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide and Example 11 (+)-4-[(5-Fluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide

The fraction-1 (126 mg) and fraction-2 (114 mg) were prepared from racemic 4-[(5-fluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N, 1,2-trimethyl-1H-benzimidazole-6-carboxamide (510 mg, STEP 3-2 in Example 9) by HPLC as follows.

Isolation Condition

Column: CHIRALCEL OJ-H (20 mm×250 mm, DAICEL)

Mobile phase: n-Hexane/Ethanol/Diethylamine (90/10/0.1)

Flow rate: 20.0 mL/min

(−)-4-[(5-Fluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benximidazole-6-carboxamide (fraction-1)

¹H NMR: spectrum data were identical with those of the racemate

optical rotation: [α]_(D) ²³=−106.8° (c=0.50, Methanol)

retention time: 7 min

(+)-4-[(5-Fluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide (fraction-2)

¹H NMR: spectrum data were identical with those of the racemate

optical rotation: [α]_(D) ²³=+103.6° (c=0.50, Methanol)

retention time: 9 min

Example 12 4-(3,4-Dihydro-2H-chromen-4-yloxy)-N,N,2-tri methyl-1H-benzimidazole-6-carboxamide

The title compound was prepared as a white solid (58 mg, 53% yield for 2 steps) from 1,1-dimethylethyl 6-[(dimethylamino)carbonyl]-4-hydroxy-2-methyl-1H-benzimidazole-1-carboxylate (100 mg, 0.313 mmol, STEP 2 in Example 9) and 3,4-dihydro-2H-chromen-4-ol (141 mg, 0.939 mmol) by the same manner in STEP 3-2 of Example 9:

¹H NMR (CDCl₃, 270 MHz) δ: 7.22-7.12 (m, 3H), 6.90-6.75 (m, 3H), 5.62-5.57 (m, 1H), 4.29-4.08 (m, 2H), 3.12-2.95 (m, 6H), 2.40 (s, 3H), 2.28-2.07 (m, 2H) ppm (—NH was not observed). MS (ESI) m/z: 352 (M+H)⁺, 350 (M−H)⁻.

Example 13 4-[8-Fluoro-5-methyl-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide

STEP 1: 8-Fluoro-5-methylchroman-4-ol STEP1-1: 3-(2-Fluoro-5-methylphenoxy)propanoic Acid

To a solution of sodium hydroxide (3.2 g, 79 mmol) in water (16 mL) was added 2-fluoro-5-methylphenol (5.0 g, 40 mmol) at room temperature. After the solution was stirred for 5 minutes, 3-iodopropionic acid (7.9 g, 40 mmol) was added to the pale yellow solution, and the mixture was refluxed with stirring for 18 hours. The mixture was cooled to room temperature, poured into 2M hydrochloric acid aqueous solution (100 mL) at 0° C., and extracted with ethyl acetate (60 mL×2). The combined extracts were washed with brine, dried over magnesium sulfate, and concentrated in vacuum. The residue was purified by column chromatography on silica gel (gradient elution from hexane/ethyl acetate 3:1 to ethyl acetate only). The resulted pale yellow solid was triturated with hexane, collected by filtration, and dried in vacuum to afford the title compound as a pale yellow solid (2.45 g, 31%).

¹H NMR (CDCl₃, 270 MHz) δ:6.95 (dd, J=11.2, 8.6 Hz, 1H), 6,81 (dd, J=7.9, 2.0 Hz, 1H), 6.75-6,66 (m, 1H), 4.30 (t, J=6.6 Hz, 2H), 2.89 (t, J=6.6 Hz, 2H), 2.30 (s, 3H) ppm. (—OH was not observed.)

STEP 1-2: 8-Fluoro-5-methyl-2,3-dihydro-4H-chromen-4-one

A mixture of 3-(2-fluoro-5-methylphenoxy)propanoic acid (2.45 g, 12.4 mmol, STEP 1-1) in polyphosphoric acid (35 g) was stirred at 100° C. for 2 hours. After cooling to room temperature, the mixture was diluted with water (150 mL), and extracted with ethyl acetate (60 mL×2). The organic layers were combined, washed with brine, dried over magnesium sulfate, and concentrated in vacuum to afford the title compound as a white solid (2.30 g, quant.).

¹H NMR (CDCl₃, 270 MHz) δ: 7.15 (dd, J=9.9, 8.6 Hz, 1H), 6.73 (dd, J=8.6, 5,3 Hz, 1H), 4.59 (t, J=6.6 Hz, 2H), 2.85 (t, J=6.6 Hz, 2H), 2.59 (s, 3H) ppm.

STEP 1-3: 8-Fluoro-5-methylchroman-4-ol

The title compound was prepared as a white solid in 93% yield (2.16 g) from 8-fluoro-5-methyl-2,3-dihydro-4H-chromen-4-one (2.30 g, 12.8 mmol, STEP 1-2) by the same manner in STEP 8-1 of Example 1.

¹H NMR (CDCl₃, 270 MHz) δ: 6.94 (dd, J=11.2, 7.9 Hz, 1H), 6.68 (dd, J=7.9, 4.6 Hz, 1H), 4.90-4.82 (m, 1H), 4.47-4.36 (m, 1H), 4.30-4.17 (m, 1H), 2.38 (s, 3H) 2.15-2.00 (m, 2H) 1.85-1.75 (m, 1H) ppm.

STEP 2: 4-[(8-Fluoro-5-methyl-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide

The title compound was prepared as a white solid in 32% yield (38 mg) from 1,1-dimethylethyl 6-[(dimethylamino)carbonyl]-4-hydroxy-2-methyl-1H-benzimidazole-1-carboxylate (100 mg, 0.31 mmol, STEP 2 in Example 9) and 8-fluoro-5-methylchroman-4-ol (0.23 g, 1.2 mmol, STEP 1-3) by the same manner in STEP 3-2 of Example 9.

¹H NMR (CDCl₃, 270 MHz) δ: 9.61 (br. s, 1H), 7.45-7.22 (m, 1H), 7.08-6.90 (m, 2H), 6.75-6.60 (m, 1H), 5.70-5.50 (m, 1H), 4.43-4.05 (m, 2H), 3.11 (br. s, 6H), 2.55 (s, 3H) 2.50-2.33 (m, 1H), 2.28-2.05 (m, 1H), 2.20 (s, 3H) ppm. MS (ESI) m/z: 384 (M+H)⁺, 382 (M−H)⁻.

Example 14 4-[(5,8-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide

STEP 1: 5,8-Difluorochroman-4-ol STEP 1-1: 3-(2,5-Difluorophenoxy)propanoic Acid

The title compound was prepared as a white solid in 37% yield (4.6 g) from 2,5-difluorophenol (8.0 g, 61 mmol) by the same manner in STEP 1-1 of Example 13.

¹H NMR (CDCl₃, 300 MHz) δ: 7.10-6.95 (m, 1H), 6.80-6.68 (m, 1H), 6.67-6.55 (m, 1H), 4.29 (t, J=6.3 Hz, 2H), 2.91 (t, J=6.3 Hz, 2H) ppm. (—OH was not observed.)

STEP 12: 5,8-Difluoro-2,3-dihydro-4H-chromen-4-one

The title compound was prepared as a brown oil in 91% yield (3.8 g) from 3-(2,5-difluorophenoxy)propanoic acid (4.6 g, 23 mmol, STEP 1-1) by the same manner in STEP 1-2 of Example 13.

¹H NMR (CDCl₃, 270 MHz) δ: 7.30-7.18 (m, 1H), 6.72-6.60 (m, 1H), 4.65 (t, J=6.3 Hz, 2H), 2.87 (t, J=6.3 Hz, 2H) ppm.

STEP 1-3: 5,8-Difluorochroman-4-ol

The title compound was prepared as a brown oil in 91% yield (3.3 g) from 5,8-difluoro-2,3-dihydro-4H-chromen-4-one (3.8 g, 21 mmol, STEP 1-2) by the same manner in STEP 8-1 of Example 1.

¹H NMR (CDCl₃, 270 MHz) δ: 7.05-6.93 (m, 1H), 6.62-6.52 (m, 1H), 5.10-5.02 (m, 1H), 4.47-4.38 (m, 1H), 4.35-4.23 (m, 1H), 2.33-2.03 (m, 3H) ppm.

STEP 2: 4-[(5,8-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide

The title compound was prepared as a white solid in 48% yield (87 mg) from 1,1-dimethylethyl 6-[(dimethylamino)carbonyl]-4-hydroxy-2-methyl-1H-benzimidazole-A-carboxylate (150 mg, 0.47 mmol, STEP 2 in Example 9) and 5,8-difluorochroman-4-ol (0.26 g, 1.4 mmol, STEP 1-3) by the same manner in STEP 3-2 of Example 9.

¹H NMR (CDCl₃, 270 MHz) δ: 7.33-7.18 (m, A H), 7.08-6.90 (m, 2H), 6.58-6.48 (m, 1H), 5.90-5.75 (m, 1H), 4.45-4.30 (m, 2H), 3.12 (br. s, 3H), 3.06 (br. s, 3H), 2.52 (s, 3H) 2.44-2.34 (m, 1H), 2.18-2.00 (m, 1H) ppm (—NH was not observed.). MS (ESI) m/z: 388 (M+H)⁺, 386 (M−H)⁻.

The following Examples 15 to 21 were prepared according to the procedure described in Example 1 or Example 2.

Example 15 4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-ethyl-N,N-dimethyl- 1H-benzimidazole-6-carboxamide

White solid ¹H NMR (CDCl₃, 270 MHz) δ: 12.23-11.00 (br. m, 1H), 7.49-6.70 (br. m, 1H), 6.97 (s, 1H), 6.50-6.15 (m, 2H), 5.96-5.48 (br. m, 1H), 4.28-4.05 (m, 2H), 3.08 (br s, 6H), 2.86-2.65 (m, 2H), 2.44-2.13 (m, 1H), 2.13-1.83 (m, 1H) 1.38-1.15 (m, 3H) ppm. MS (ESI) m/z: 402 (M + H)⁺, 400 (M − H)⁻. Example 16 N,N,2-Trimethyl-4-[(5-methyl-3,4-dihydro-2H-chromen-4-yl)oxy]-1H- benzimidazole-6-carboxamide

White solid ¹H NMR (CDCl₃, 270 MHz) δ: 10.06-9.52 (br. m, 1H), 7.37 (s, 1H), 7.28-7.16 (m, 1H), 7.05 (s, 1H), 6.90-6.68 (m, 2H), 5.97-5.53 (br m, 1H), 4.33-4.06 (m, 2H), 3.11 (br. s, 6H), 2.60-2.48 (br m, 3H), 2.47-2.35 (m, 1H), 2.28-2.20 (br. m, 3H), 2.25-2.05 (m, 1H) ppm. MS (ESI) m/z: 366 (M + H)⁺, 364 (M − H)⁻. Example 17 (−)-N,N,2-Trimethyl-4-[(5-methyl-3,4-dihydro-2H-chromen-4-yl)oxy]-1H- benzimidazole-6-carboxamide optical rotation: [α]_(D) ²¹ = −49.2° (c = 0.51, Methanol) Example 18 (+)-N,N,2-Trimethyl-4-[(5-methyl-3,4-dihydro-2H-chromen-4-yl)oxy]-1H- benzimidazole-6-carboxamide optical rotation: [α]_(D) ²¹ = +53.0° (c = 0.51, Methanol) Example 19 N,2-Dimethyl-4-[(5-methyl-3,4-dihydro-2H-chromen-4-yl)oxy]-1H- benzimidazole-6-carboxamide

White solid ¹H NMR (CDCl₃, 300 MHz) δ: 9.80-9.50 (br. s, 1H), 7.65-7.45 (m, 2H), 7.27-7.15 (m, 1H), 6.88-6.73 (m, 2H), 6.40-6.25 (m, 1H), 5.80-5.60 (m, 1H), 4.30-4.05 (m, 2H), 3.05 (d, J=5.1 Hz, 3H), 2.57 (s, 3H), 2.48-2.35 (m, 1H), 2.25-2.10 (m, 1H), 2.21 (s, 3H) ppm. MS (ESI) m/z: 352 (M + H)⁺, 350 (M − H)⁻. Example 20 2-Methyl-4-[(5-methyl-3,4-dihydro-2H-chromen-4-yl)oxy]-6-(pyrrolidin- 1-ylcarbonyl)-1H-benzimidazole

White solid ¹H NMR (CDCl₃, 270 MHz) δ: 11.35-10.20 (br. m, 1H), 7.45 (br. s, 1H), 7.25-6.90 (m, 2H), 6.85-6.60 (m, 2H), 5.95-5.48 (br. m, 1H), 4.30-3.97 (m, 2H), 3.75-3.40 (m, 4H), 2.48 (s, 3H), 2.43-2.27 (m, 1H), 2.21 (s, 3H), 2.15-1.80 (m, 5H) ppm. MS (ESI) m/z: 392 (M + H)⁺, 390 (M − H)⁻. Example 21 4-[(7-Fluoro-5-methyl-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N,2- trimethyl-1H-benzimidazole-6-carboxamide

White solid ¹H NMR (CDCl₃, 300 MHz) δ: 9.60 (br. s, 1H), 7.50-7.15 (m, 1H), 7.10-6.80 (m, 1H), 6.63-6.30 (m, 2H), 5.65-5.40 (m, 1H), 4.35-4.05 (m, 2H), 3.10 (br. s, 6H), 2.54 (s, 3H), 2.50-2.02 (m, 2H), 2.23 (s, 3H) ppm. MS (ESI) m/z: 384 (M + H)⁺, 382 (M − H)⁻.

Example 22 (−)-6-(Azetidin-1 ylcarbonyl)-4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-1H-benzimidazole

STEP 1: (−)-4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-1H-benzimidazole-6-carboxylic Acid

To a stirred mixture of 1-(1,1-dimethylethyl) 6-methyl 4-hydroxy-2-methyl-1H-benzimidazole-1,6-dicarboxylate (1.33 g, 4.34 mmol, STEP 3 in Example 4), (+)-5,7-difluoro-3,4-dihydro-2H-chromen-4-ol (1.82 g, 9.79 mmol, STEP 8 in Example 2) and triphenylphosphine (2.28 g, 8.69 mmol) in toluene (50 mL) was added diisopropyl azodicarboxylate (DIAD) (1.76 g, 8.70 mmol) at room temperature. The reaction mixture was stirred at room temperature for 30 minutes and concentrated in vacuum. The residue was dissolved in methanol (20 mL) and tetrahydrofuran (5 mL), and to the mixture was added 4M lithium hydroxide aqueous solution (18.0 mL, 90.0 mmol) at room temperature. After stirring for 1 hour at 80° C., the reaction mixture was concentrated in vacuum. The residue was dissolved with water (200 mL), acidified with 2M hydrochloric acid aqueous solution (50 mL), and extracted with ethyl acetate (200 mL×3). The organic layers were combined, dried over magnesium sulfate and concentrated in vacuum. The residue was purified by column chromatography on silica gel (gradient elution from ethyl acetate only to ethyl acetate:methanol with 1 wt % of acetic acid=3:1) to afford the title compound as a white solid (1.15 g, 73%, >99% ee).

¹H NMR: spectrum data were identical with those of the racemate (STEP 4 in Example 4).

optical rotation: [α]_(D) ²⁴=−78.7° (c=0.50, Methanol).

STEP 2: (−)-6-(Azetidin-1-ylcarbonyl)-4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-1H-benzimidazole

The title compound was prepared as a white solid (132 mg, 79%) from (−)-4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-1H-benzimidazole-6-carboxylic acid (150 mg, STEP 1) and azetidine hydrochloride (117 mg, 1.25 mmol) by the same manner in STEP 5 of Example 1.

¹H NMR (CDCl₃, 270 MHz) δ: 7,40 (s, 1H), 7.20 (s, 1H), 6.42-6.25 (m, 2H), 5.87-5.62 (m, 1H), 4.46-3.94 (m, 6H), 2.51 (s, 3H), 2.42-2.19 (m, 3H), 2.19-1.78 (m, 1H) ppm (—NH was not observed). MS (ESI) m/z: 400 (M+H)⁺, 398 (M−H)⁻.

optical rotation: [α]_(D) ²⁴=−98.0° (c=1.00, Methanol).

Following Examples 23 and 24 were prepared from (−)-4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-1H-benzimidazole-6-carboxylic acid (Step 1 in Example 22) and the corresponding various amines according to the procedure described in Step 5 of Example 1.

Example 23 (−)-4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N-ethyl-N,2- dimethyl-1H-benzimidazole-6-carboxamide

White solid ¹H NMR (CDCl₃, 270 MHz) δ: 9.65 (s, 1H), 7.37 (s, 1H), 6.97 (s, 1H), 6.57-6.19 (m, 2H), 5.72-5.41 (m, 1H), 4.36-4.20 (m, 2H), 3.48 (br. s, 2H), 3.05 (br. s, 3H), 2.54 (s, 3H), 2.35-2.30 (m, 1H), 2.11-1.96 (m, 1H), 1.27-1.10 (m, 3H) ppm. MS (ESI) m/z: 402 (M + H)⁺, 400 (M − H)⁻. optical rotation: [α]_(D) ²⁴ = −101.6° (c = 1.00, Methanol) Example 24 (−)-4-[(5,7-Difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-6- (morpholin-4-ylcarbonyl)-1H-benzimidazole

White solid ¹H NMR (CDCl₃, 270 MHz) δ: 9.33 (s, 1H), 7.37 (s, 1H), 7.03 (s, 1H), 6.52-6.37 (m, 2H), 5.65 (s, 1H), 4.39-4.26 (m, 2H), 3.91-3.49 (m, 8H), 2.60 (s, 3H), 2.47-2.33 (m, 1H), 2.17-2.01 (m, 1H) ppm. MS (ESI) m/z: 430 (M + H)⁺, 428 (M − H)⁻. optical rotation: [α]_(D) ²⁴ = −97.7° (c = 1.00, Methanol). The following Examples 25 was prepared according to the procedure described in Example 1.

Example 25 4-(3,4-Dihydro-2H-thiochromen-4-yloxy)-N,N,2-trimethyl-1H-benzimi- dazole-6-carboxamide

White solid ¹H NMR (CDCl₃, 270 MHz) δ: 7.35-7.10 (m, 4H), 7.05-6.82 (m, 2H), 5.85-5.50 (broad m, 1H), 3.43-3.25 (m, 1H), 3.20-2.95 (m, 6H), 2.88-2.75 (m, 1H), 2.70-2.57 (m, 1H), 2.49 (s, 3H), 2.23-2.02 (m, 1H) ppm (—NH was not observed). MS (ESI) m/z: 368 (M + H)⁺, 366 (M − H)⁻.

All publications, including but not limited to, issued patents, patent applications, and journal articles, cited in this application are each herein incorporated by reference in their entirety.

Although the invention has been described above with reference to the disclosed embodiments, those skilled in the art will readily appreciate that the specific experiments detailed are only illustrative of the invention. It should be understood that various modifications can be made without departing from the spirit of the invention. Accordingly, the invention is limited only by the following claims. 

1. A compound of the formula (I):

or a pharmaceutically acceptable salt thereof, wherein: -A-B— represents —O—CH₂—, —S—CH₂—, —CH₂—O— or —CH2—S—; X represents an oxygen atom or NH; R¹ represents a C₁-C₆ alkyl group being unsubstituted or substituted with 1 to 2 substituents independently selected from the group consisting of a hydroxy group and a alkoxy group; R² and R³ independently represent a hydrogen atom, a C₁-C₆ alkyl group, a C₃-C₇ cycloalkyl group or a heteroaryl group selected from 2-thienyl, 2-thiazolyl, 4-thiazolyl, 2-furyl, 2-oxazolyl, 1-pyrazolyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrazinyl and 2-pyrimidinyl, said C₁-C₆ alkyl group, said C₃-C₇ cycloalkyl group and said heteroaryl group being unsubstituted or substituted with 1 to 3 substituents independently selected from the group consisting of a halogen atom, a hydroxy group, a C₁-C₆ alkoxy group, a C₃-C₇ cycloalkyl group, an amino group, a C₁-C₆ alkylamino group, and a di(C₁-C₆ alkyl)amino group; or R² and R³ taken together with the nitrogen atom to which they are attached form a 4 to 6 membered heterocyclic group being unsubstituted or substituted with 1 to 2 substituents selected from the group consisting of a hydroxy group, a C₁-C₆ alkyl group, a C₁-C₆ acyl group and a hydroxy-C₁-C₆ alkyl group; R⁴, R⁵, R⁶ and R⁷ independently represent a hydrogen atom, a halogen atom, a hydroxy group, a C₁-C₆ alkyl group or a C₁-C₆ alkoxy group; and R⁸ represents a hydrogen atom, a hydroxy group or a C₁-C₆ alkoxy group.
 2. The compound or the pharmaceutical acceptable salt thereof of claim 1, wherein: X is an oxygen atom; R² and R³ are independently a C₁-C₆ alkyl group or a C₃-C₇ cycloalkyl group, said C₁-C₆ alkyl group and said C₃-C₇ cycloalkyl group being unsubstituted or substituted with 1 to 3 substituents independently selected from the group consisting of a halogen atom, a hydroxy group, a C₁-C₆ alkoxy group, a C₃-C₇ cycloalkyl group and a di(C₁-C₆ alkyl)amino group; or R² and R³ taken together with the nitrogen atom to which they are attached form an azetidinyl group, a pyrrolidinyl group, a piperazinyl group or a morpholino group, said azetidinyl group, said pyrrolidinyl group, said piperazinyl group and said morpholino group being unsubstituted or substituted with a substituent selected from the group consisting of a hydroxy group, a C₁-C₆ alkyl group, a C₁-C₆ acyl group and a hydroxy-C₁-C₆ alkyl group; R⁴, R⁵, R⁶ and R⁷ are independently a hydrogen atom, a halogen atom or a C₁-C₆ alkyl group; and R⁸ is a hydrogen atom.
 3. A pharmaceutical composition comprising the compound or the pharmaceutically acceptable salt thereof of claim 2, and at least one pharmaceutically acceptable carrier.
 4. The compound or the pharmaceutical acceptable salt thereof of claim 1, wherein: -A-B— is —O—CH₂— or —CH₂—O—; X is an oxygen atom; R¹ is a C₁-C₆ alkyl group; R² and R³ are independently a C₁-C₆ alkyl group being unsubstituted or substituted with 1 to 3 substituents independently selected from the group consisting of a hydroxy group and a C₁-C₆ alkoxy group and; or R² and R³ taken together with the nitrogen atom to which they are attached form a pyrrolidinyl group being unsubstituted or substituted with a substituent selected from the group consisting of a hydroxy group, a C₁-C₆ alkyl group and a hydroxy-C₁-C₆ alkyl group; R⁴, R⁵, R⁶ and R⁷ are independently a hydrogen atom, a halogen atom or a C₁-C₆ alkyl group; and R⁸ is a hydrogen atom.
 5. A pharmaceutical composition comprising the compound or the pharmaceutically acceptable salt thereof of claim 4, and at least one pharmaceutically acceptable carrier.
 6. A compound selected from: 4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxyl]-N,N,2-trimethyl-1H-benzimidazole -6-carboxamide; 4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxyl]-2-methhyl-6-(pyrrolidin-1-ylcarbonyl)-1H-benzimidazole; 4-[(5-fluoro-3,4-dihydro-2H-chromen-4-yl)oxyl]-N,N,2-trimethyl-1H-benzimidazole-6-carboxamide; or a pharmaceutically acceptable salt thereof.
 7. A compound selected from: (−)-4-[((4S)-5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxyl]-N,N,2-trimethyl-1H -benzimidazole-6-carboxamide; (−)-4-[(5,7-difluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-2-methyl-6-(pyrrolidin- 1-ylcarbonyl)-1H-benzimidazole; (−)-4-[(5-fluoro-3,4-dihydro-2H-chromen-4-yl)oxy]-N,N2-trrimethyl-1H-benzimdiazole -6-carboxamide; or a pharmaceutically acceptable salt thereof.
 8. A pharmaceutical composition comprising the compound or the pharmaceutically acceptable salt thereof of claim 7, and at least one pharmaceutically acceptable carrier. 